Title of Invention	"METHOD OF CONTINUOUSLY TRNASMITTING USER DATA ONREVERSE COMMON CHANNEL IN MOBILE COMMUNICATION SYSTEM".
Abstract	A method is provided of continuously transmitting user data on a reverse common channel in a mobile communication system without a reverse dedicated channel. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. The plurality of segmented messages are then transmitted in the data segments of consecutive frames on the reverse common channel. The method further comprises determining whether a base station receives the segmented messages by receiving a response message indicating reception of the segmented messages. The common channel is preferably a power-controlled logical dedicated channel.

Title of Invention

"METHOD OF CONTINUOUSLY TRNASMITTING USER DATA ONREVERSE COMMON CHANNEL IN MOBILE COMMUNICATION SYSTEM".

Abstract

A method is provided of continuously transmitting user data on a reverse common channel in a mobile communication system without a reverse dedicated channel. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. The plurality of segmented messages are then transmitted in the data segments of consecutive frames on the reverse common channel. The method further comprises determining whether a base station receives the segmented messages by receiving a response message indicating reception of the segmented messages. The common channel is preferably a power-controlled logical dedicated channel.

Full Text	CLAIM OF PRIORITY This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled METHOD OF CONTINUOUSLY TRANSMITTING PACKET DATA ON REVERSE COMMON CHANNEL IN MOBILE COMMUNICA TION SYSTEM earlier filed in the Korean Industrial Property Office on 14 Apr. 1998, and there duly assigned Serial No. 98-14275. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a mobile communication system, and in particular, to the next generation mobile communication system for providing multimedia data services. 2. Description of the Related Art The third generation (3G) IS-95 supports services for transmission of high quality voice, high speed data, and moving pictures, and internet browsing. In this mobile communication system, a forward link is directed from a base station (BS) to a mobile station (MS) and a reverse link is directed from the MS to the BS. A paging channel and an access channel (referred to as reverse common channels) are used to transport data between a BS 4 and an MS 2 before a voice call set-up, as shown in FIG. 10. The BS 4 sends a message on the paging channel and receives a response message from the MS 2 on the access channel. The MS 2 sends a message on the access channel and receives a response message from the BS 4 on the paging channel. A plurality of paging channels and access channels are available for use. The paging channels are identified by Walsh codes and the access channels are identified by long codes. The existing 3GIS-95 is well established for voice communication but fails to fully ensure an intended communication quality for packet data communication, though a large amount of packet data including a long burst period and an idle period is transmitted by an RLP (Radio Link Protocol) and short burst data is transmitted by an RBP (Radio Burst Protocol). RBP is the transmission scheme of determining whether to retransmit the same SDB (Short Data Burst) frame or to send another SDB frame depending on an acknowledgement signal ACK/negative acknowledgement signal NACK received for the previously sent SDB frame, in a dormant state of the 3G IS-95. Thus, the RBP transmission scheme is poor in terms of response time and gain rate, and shows a relatively low transmission efficiency because it is confined to a burst substate of the dormant state. Since the RBP is implemented on a reverse common channel, a response is delayed and reliability is low. In particular, the procedure of sending an SDB frame, receiving a response, and then sending another SDB frame causes a long delay time. SUMMARY OF THE INVENTION - 2 - It is an object of the present invention, therefore, to provide a method of continuously transmitting a long burst message on a reverse common channel. . It is another object of the present invention to provide a method of implementing a full-duplex RBP transmission scheme in which an SDB message is continuously transmitted in a dormant state. It is a further object of the present invention to provide a method of enabling a long-burst RBP transmission when a power control is performed on a designated reverse common channel to appropriately control an initial system access power, to thereby minimize a response time and increase transmission efficiency. It is a still further object of the present invention to provide a method of continuously transmitting burst data without implementing an RLP by setting a control channel when transiting a dormant state or a suspended state to a control hold state or an active state. To achieve the above objects, there is provided a method of transmitting user data on a reverse common channel with a reverse dedicated channel released. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. Then, the plurality of segmented messages are transmitted in the data segments of consecutive frames on the reverse common channel, and it is determined whether a base station receives the segmented messages. BRIEF DESCRIPTION OF THE/DRAWINGS - 3 - The above objects and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which: FIG. 1A is a flowchart of transmitting an SDB message from an MS on a reverse common channel in a burst substate of a dormant state, as proposed in the existing 3GIS-95; FIG. 1B is a flowchart of receiving an SDB message in a BS on a reverse common channel in a burst substate of a dormant state, as proposed in the existing 3G IS-95; FIG. 2 illustrates the exchange of messages between the BS and the MS of FIGs. 1A and 1B; FIG. 3A illustrates the structure of an SDB frame in a continuous RBP transmission scheme according to an embodiment of the present invention; FIG. 3B illustrates the structure of a response frame for a received message in the continuous RBP transmission scheme according to the embodiment of the present invention; FIG. 4A illustrates the exchange of messages and an error correcting operation upon generation of a negative acknowledgement signal NACK in a first embodiment of the continuous RBP transmission scheme in which the negative acknowledgement signal NACK is transmitted only for an error-having SDB frame; FIG. 4B illustrates the exchange of messages and an error correcting operation upon loss of a negative acknowledgement signal NACK in the first embodiment of the continuous RBP transmission scheme; FIG. 4C illustrates the exchange of messages and an error correcting operation upon loss of an MS initiated SDB frame in the first embodiment of the - 4 - continuous RBP transmission scheme; FIG. 5 is a flowchart of an MS operation in the first embodiment of the continuous RBP transmission scheme; FIG. 6 is a flowchart of a BS operation in the first embodiment of the continuous RBP transmission scheme; FIG. 7A illustrates the exchange of messages and an error correcting operation upon generation of a negative acknowledgement signal NACK in a second embodiment of the continuous RBP transmission scheme in which a response signal ACK or NACK is transmitted for each received SDB frame; FIG. 7B illustrates the exchange of messages and an error correcting operation upon loss of a response signal ACK or NACK in the second embodiment of the continuous RBP transmission scheme; FIG. 7C illustrates the exchange of messages and an error correcting operation upon loss of an MS initiated SDB frame in the second embodiment of the continuous RBP transmission scheme; FIG. 8 is a flowchart of an MS operation in the second embodiment of the continuous RBP transmission scheme; FIG. 9 is a flowchart of a BS operation in the second embodiment of the continuous RBP transmission scheme; FIG. 10 is a view of channels used by the BS and the MS before a voice call set-up; and FIG. 11 is a view of packet service (MAC) states in a communication system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS - 5 - Preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Like reference numerals denote the same components in the drawings. It is to be noted that a detailed description of the well-known function or structure of the present invention will be omitted if it is deemed to obscure the subject matter of the present invention. For better understanding of the present invention, packet service states in a communication system will be described referring to FIG. 11. As shown, a packet service is composed of packet null state, initialization state, active state, control hold state, suspended state, dormant state, and reconnect state. Packet service options are connected in the control hold state, active state, and suspended state. The packet null state refers to a default state prior to activation of the packet service. Upon request for a packet service in the packet null state, a connection to the packet service is attempted in the initialization state. When a dedicated control channel (DCCH) is set, the initialization state transitions to the control hold state. The DCCH is needed to initialize an RLP and a PPP (Point-to-Point Protocol). In the active state, forward and reverse DCCHs and dedicated traffic channels DTCHs) are maintained and RLP frames are exchanged on the channels. When a relatively short inactive period is produced, the packet service enters the suspended state to efficiently use the radio resources and reduce power consumption of the MS. While the DCCHs are released in the suspended state, both the BS and MS reserve the information of RLP status, traffic channel assignment, encryption variables, and the like and thus can relatively easily be assigned the DCCHs. In the suspended state, the MS monitors a forward packet paging channel. Upon - 6 - designation of a DCCH, the suspended state transitions to the control hold state. If a packet is not received for a predetermined time in the suspended state, the dormant state is entered. The dormant state is composed of an idle substate and a burst substate and refers to the state where packet service options, control and traffic channels, and the RLP are released, with only the PPP maintained. The dormant state transitions to the packet null state if the PPP is released. FIGs. 1A and 1B are flowcharts of an MS operation for transmitting an SDB message and a BS operation for receiving the SDB message on a reverse common channel in the burst substate of the dormant state in the existing 3G IS-95. After the MS 2 sends an SDB frame on a reverse common channel (i.e., access channel), reception of an acknowledgement signal ACK from the BS 4 on a paging channel indicates a successful transmission, but reception of a negative acknowledgement signal NACK or failure to receive a response message from the BS 4 for a predetermined time, that is, until a timer T_RBP has expired, indicates a failed transmission. The BS 4 checks the CRC (Cyclic Redundancy Code) of the SDB frame received on the reverse common channel (access channel) and sends the acknowledgement signal ACK or the negative acknowledgement signal NACK on the paging channel. Referring to FIGs. 1A and 1B, the MS 2 sends an SDB frame on a reverse common channel and sets the timer T_RBP in step 100. The BS 4 determines whether the SDB frame is received on the reverse common channel in step 112. If it is, the BS 4 checks the CRC of the SDB frame in step 114 and determines the presence or absence of errors in the SDB frame in step 116. If no CRC errors were generated, the BS 4 sends the MS 2 the acknowledgement signal ACK indicating 7 _ a successful transmission on the paging channel, in step 118. If CRC errors were found, the BS 4 sends the MS 2 the negative acknowledgement signal NACK or a message indicating a failed transmission in step 120. The MS 2 determines whether the signals ACK or NACK are received before the timer T_RBP has expired, in steps 102 and 104. Upon receipt of the signal ACK, the MS 2 determines whether there is another SDB frame to send in step 106. If there is, the procedure returns to step 100. Otherwise, the procedure ends. If the signal NACK or the message indicating a failed transmission are received before the timer T_RBP has expired, or if none of the signals ACK and NACK, and the message indicating a failed transmission are received until the timer T_RBP has expired in steps 102 and 104, the MS 2 retransmits the same SDB frame and resets the timer T_RBP in step 110. Then, the procedure goes back to step 102. FIG. 2 is a flowchart illustrating the exchange of messages between the BS 2 and the MS 4 of FIGs. 1A and 1B on the basis of the protocol. An embodiment of the present invention is directed to transmission of a long burst message by modifying the RBP transmission scheme described referring to FIGs. 1A, 1B, and 2 in the existing 3GIS-95. To do so, designation of a common channel and power control of the designated common channel should precede. A well-recognized example of the common channel designation is disclosed in Korea Application No. 1998-13149 filed on 13 April, 1998 and entitled "Device and Method for Transmitting Common Channel Message in CDMA Communication System" by Ki-Sung JUNG, et. al.. A detailed description of power control of a designated channel can be found in Korea Application No. 1998-14276 filed on 14 April, 1998 and entitled "Power Control of Reverse Common Channel in CDMA Communication System" by Jin-Woo CHOI, et. al.. The designation of a common channel (see Korea Application No. 1998-13149) refers to the process of designating a reverse common channel as dedicated (hereinafter, designated common channel) in a logical sense of the term when a message longer than one frame is generated in order to continuously transmit the long message. More specifically, upon generation of a message to send, the MS 2 determines whether the message can be sent at one time. If it can be, the conventional RBP transmission scheme is used. Otherwise, the long message is divided into frame segments, and a more message flag and a designation request flag of a frame message are set prior to transmission to the BS 4. Upon receipt of the frame message, the BS 4 monitors the more message flag and the designation request flag. If they are cleared, the BS 4 clears a designation flag and sends an acknowledgement to the MS 2. If either of the more flag message and the designation request flag is set, the BS 4 determines whether there is a channel to designate and if there is, it designates the channel. The BS 4 sets a maximum duration and a priority for the designated channel when necessary, and sends the acknowledgement message to the MS 2. Now turning to the power control of the designated channel (see Korea Patent No. 1998-14276), since the BS 4 receives SDB frames continuously, a - 9 - message sent by the BS 4 should include information on the above-described channel designation and whether to perform a power control, and the Walsh code number of a common power control channel and the location (i.e., slot index) of a power control signal if the power control is performed. A predetermined time after the BS 4 sends a response message for the designated channel request to the MS 2, it sends a power control signal in. a predefined slot on a power control dedicated channel at predetermined intervals. Then, the MS 2 sends preambles on the channel designated by the response message for a predetermined time and adjusts transmit power between the BS 4 and the MS 2. The MS 2 sends a transmit message to the BS 4 on the designated common channel a predetermined time later. While the BS 4 receives the message from the MS 2, it continuously controls power by sending the power control signal on the common power control channel. An RBP for continuous SDB message transmission can be implemented in the embodiments of the present invention if the afore-described channel requirements of common channel designation and power control of a designated channel are satisfied. Implementation of the RBP for continuous SDB frame transmission according to the embodiments of the present invention requires an SDB frame shown in FIG. 3A and a response frame for a received message, shown in FIG. 3B. The SDB frame and the response frame are sent by the MS 2 and the BS 4, respectively. In FIG. 3A, the SDB frame is comprised of an SDB user data field 10, a - 10 - transmitted SDB sequence field 12, and a more flag field 14. The transmitted SDB sequence field 12 provides the sequence number of an SDB frame to be continuously transmitted from the MS 2, and the more flag field 14 indicates whether there is an SDB frame following the current SDB frame. In FIG. 3B, the response frame is comprised of a response field 20 and a received SDB sequence field 22. The response field 20 informs the MS 2 of the presence or absence of errors in a received message by the signal ACK or NACK. The received SDB sequence field 22 provides the sequence number of the currently received SDB frame. The transmitted and received SDB sequence fields 12 and 22 contain the same bits. An SDB message is transmitted continuously in two ways depending on a response from the BS 4: the signal NACK is sent only if the BS 4 detects errors; and the signal ACK or NACK is sent for each SDB frame received from the MS FIGs. 4A to 6 illustrate the first embodiment of the continuous RBP transmission scheme according to the present invention, and FIGs. 7A to 9 illustrate the second embodiment of the continuous RBP transmission scheme. FIG. 4A is a flowchart of a message transmission/reception and an error correcting operation upon receipt of the signal NACK in the first embodiment of the RBP transmission scheme where the signal NACK is transmitted only for an error-having SDB frame. The MS 2 receives a response message shown in FIG. 3B from the BS 4 while the MS 2 sends SDB frames continuously on a power-controlled designated common channel. Upon receipt of the response message - 11 - including the signal NACK, the MS 2 detects an error-having SDB frame by checking the received SDB sequence field 22 of the response message and retransmits the corresponding SDB frame. When the continuous RBP transmission procedure is completed, the BS 4 releases the power-controlled designated common channel and then reassembles received SDB frames based on an SDB sequence to construct a complete SDB message. FIG. 4B is a flowchart of an error correcting operation when the MS 2 fails to receive the signal NACK due to characteristics inherent to a radio environment. If an SDB frame received from the MS 2 has errors, the BS 4 sends a response message having the signal NACK and a corresponding received SDB sequence number, and sets a timer T_NACK. If the SDB frame corresponding to the received SDB sequence number is not received from the MS 2 until the timer T_NACK has expired, the BS 4 considers the signal NACK to have been lost and retransmits the signal NACK. The MS 2 considers the SDB frame successfully transmitted since it does not receive the signal NACK, and retransmits the SDB frame corresponding to the received SDB sequence number of the NACK response message only when it receives the signal NACK from the BS 4. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and then reassembles the received SDB frames based on an SDB sequence to construct a complete SDB message. FIG. 4C illustrates an error correcting operation when an MS initiated SDB frame is lost, during transmission. The BS 4 receives an SDB frame and checks the more flag field 14 of the SDB frame. If the more flag field 14 is set, the BS 4 sets - 12 - a timer T_SDB and awaits the next SDB frame from the MS 2. If the BS 4 does not receive the next SDB frame until the timer T_SDB has expired, the BS 4 sends the MS 2 a response message with the response field set to NACK and the received SDB sequence field set to a sequence number following the transmitted SDB sequence number of the most recently received SDB frame which was MS initiated for the first time. The MS 2 considers the transmission of its initiated message successful until it receives the signal NACK. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and then reassembles received SDB frames based on an SDB sequence to construct a complete SDB message. FIGs. 5 and 6 are flowcharts of an MS operation and a BS operation for a message communication described referring to FIGs. 4A, 4B, and 4C. FIG. 5 is a flowchart of the MS operation in the first embodiment of the continuous RBP transmission scheme, and FIG. 6 is a flowchart of the BS operation in the first embodiment of the continuous RBP transmission scheme. Referring to FIGs. 5 and 6, upon generation of an SDB message to send in step 200 of FIG. 5, the MS 2 determines whether the SDB message contains two or more frames in step 202. If the SDB message is one frame, the SDB message is sent to the BS 4 in the conventional RBP transmission scheme. If the SDB message should be sent in two ore more frames, the MS 2 requests assigmnent of a designated common channel from the BS 4 in step 206. Upon receipt of the request for a designated common channel in step 300 of FIG. 6, the BS 4 determines whether there is an available designated common - 13 - channel in step 302. If the request is not acknowledgeable, the BS 4 sends the MS 2 a message having a designation flag cleared in step 304. If it is acknowledgeable, the BS 4 assigns a power-controlled designated common channel and sends a message having a designation flag set to the MS 2, in step 306. The MS 2 determines whether the designation flag of the received message is set, in step 208. If it is not, the MS 2 resumes the request for a designated common channel in step 206. If it is, the MS 2 divides the SDB message into frame segments in step 210. The SDB segments are SDB user data recorded in the SDB user data field 10 shown in FIG. 3A. In step 212, the MS 2 sets the more flag field 14 and marks an SDB sequence number on the transmitted SDB sequence field 12. If the last SDB segment is to be sent, the more flag field 14 is reset. The MS 2 determines whether a response message is received from the BS 4, in step 214. When no response message is received, the MS 2 sends an SDB frame including the marked more flag and transmitted SDB sequence number and the SDB user data to the BS 4 on the power-controlled designated common channel in step 216. Then, the MS 2 determines whether the currently sent SDB frame is the last one, in step 218. If it is not, the procedure returns to step 210. Meanwhile, the BS 4 determines whether the SDB frame is received in step 308. Upon receipt of the SDB frame, the BS 4 checks the CRC of the SDB frame and determines whether it has an error in step 310. If there are no errors, the BS 4 determines whether the received SDB frame was retransmitted by the MS 2 for the signal NACK, in step 312. If it is transmitted for the first time, the BS 4 determines whether the more flag of the SDB frame is set, in step 316. If the more flag is set, the BS 4 sets the timer T SDB to correct errors if a following SDB frame is not - 14 - received, in step 318. If the more flag is not set, the procedure goes to step 310. In step 328, the BS 4 determines whether the timer T_NACK has expired. The timer T_NACK is set to send the signal NACK from the BS 4 and thus not used when an SDB frame is normally received. If the timer T_NACK has not expired, the BS 4 goes back to step 308. In accordance with the embodiment of the present invention, the BS 4 sends no response message if an SDB frame is successfully received. For example, FIG. 4A shows that the BS 4 sends no response message for the successfully received SDB frames (1), (2), and (4). Here, (1), (2), and (4) denote the sequence numbers of the SDB frames. Returning to FIG. 6, if a CRC error is found in the received SDB frame in step 310, the BS 4 sends the signal NACK to the MS 2 in step 320. That is, the sequence number of the error-having SDB frame is marked on the received SDB sequence field 22 of FIG. 3B and the signal NACK is marked on the response field 20. By way of example, if the SDB frame (3) has errors, the BS 4 sends a response message containing the signal NACK (3) in FIG. 4A. The BS 4 sets the timer T_NACK in step 322 to correct errors when the signal NACK is not reliably sent to the MS 2 as shown in FIG. 4B. Upon receipt of the response message including the signal NACK (3) from the BS 4, the MS 2 checks the received SDB sequence field 22 of the response message in step 221. The MS 2 retransmits the SDB frame (SDB frame (3) in FIG. 4A) corresponding to the sequence number in step 222. It is optional for the BS 4 to send a signal ACK(3) for the retransmitted SDB frame (3) to the MS 2, and for - 15 - the MS 2 to determine whether the signal ACK(3) is received until the timer T_RBP has expired. For example, even if the BS 4 sends no response message for the retransmitted SDB frame (3) until the timer T RBP has expired, the MS 2 considers the transmission successful. If the MS 2 fails to receive the response message including the signal NACK(3), the MS 2 considers the previous SDB frame transmission successful and sends the next SBD frame to the BS 4. If the SDB frame for which the signal NACK is generated is not received until the timer T_NACK has expired in steps 308 and 328; the BS 4 retransmits the signal NACK to the MS 2, in step 330. Then, the BS 4 resets the timer T_NACK in step 332. From FIG. 4B, it is noted that the BS 4 resends the signal NACK (3) to the MS 2 when the timer T_NACK has expired. Meanwhile, if the BS 4 fails to receive an SDB frame until the timer T_SDB has expired in steps 308 and 324, it sends the MS 2 a response message having the signal NACK and a sequence number following the most recently received SDB frame which was transmitted from the MS 2 for the first time marked on the received SDB sequence field 22, in step 326. The BS 4 sets the timer T_SDB in step 318 and goes to step 328. Referring to FIG. 4C, when the timer T_SDB has expired, the BS 4 sends a signal NACK(4) corresponding to the sequence number (4) following the most recently received SDB frame (3). In step 218 of FIG. 5, the MS 2 determines whether a current SDB frame is the last one, and in step 224, it sets the timer T_RBP. Then, the MS 2 determines whether a response message is received from the BS 4 in step 226. - 16 - On the other hand, if the BS 4 receives the last SDB frame (more flag reset) in step 314, it sends a response message including the signal ACK indicating completed reception to the MS 2 in step 334. The BS 4 releases the power-controlled designated common channel in step 336, and reassembles received SDB frames to construct a complete SDB message in step 338. If the MS 2 fails to receive a response message until the timer T_RBP has expired in steps 226 and 227, it retransmits the most recently sent SDB frame in step 238. Upon receipt of the response message, the MS 2 determines whether the response field 20 of the response message indicates an acknowledgement in step 236. In the case of a negative acknowledgement, the MS 2 retransmits the most recently sent SDB frame in step 238. If a message received within the duration of the timer T_RBP is not a response message for the most recently sent message in steps 226 and 228, the MS determines whether the response field 20 of the response message is set to ACK in step 230. If the response field 20 is set to NACK, the MS 2 detects the sequence number from the received SDB sequence field 20 of the response message and retransmits the SDB frame corresponding to the detected sequence number to the BS 4, in step 234. Then, a description of the second embodiment of the RBP transmission scheme where a signal ACK or NACK is generated for each SDB frame received from the MS 2 will be given referring to FIGs 3A and 3B, FIGs. 7A, 7B, and 7C, and FIGs. 8 and 9. - 17 - FIG. 7A illustrates a message communication and an error correcting operation upon generation of the signal NACK in the second embodiment of the RBP transmission scheme where the signal ACK is generated for an error-free SDB frame and the signal NACK is generated for an error-having SDB frame. The MS 2 receives a response message from the BS 4 while continuously transmitting SDB frames on a power-controlled designated common channel. If the response message contains the signal NACK, the MS 2 detects an error-having SDB frame by checking the received SDB sequence field 22 of the response message and retransmits the corresponding SDB frame. When the continuous RBP transmission scheme is completed, the BS 4 releases the power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message. FIG. 7B illustrates an error correcting operation when the MS 2 fails to receive a response signal ACK or NACK from the BS 4 due to characteristics inherent to a radio environment. The MS 2 sends an SDB frame and sets the timer T_RBP. If the signal ACK or NACK with the sequence number of the sent SDB frame is not received until the timer T_RBP has expired, the MS 2 considers that the SDB frame has errors and retransmits the SDB frame. Alternatively, the MS 2 determines whether to retransmit the SDB frame by setting the timer T_ACK to check a response from the BS 4. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message. FIG. 7C illustrates an error correcting operation when an MS initiated SDB - 18 - frame is lost during transmission. The BS 4 receives an SDB frame and monitors the more flag field 14 of the SDB frame. If the more flag is set, the BS 4 sets the timer T_SDB and awaits the next SDB frame from the MS 2. If no SDB frame is received until the timer T SDB has expired, the BS 4 sends the MS 2 a response message including the signal NACK and the sequence number following the transmitted sequence number of the most recently received SDB frame. This error correction can be performed in the MS 2. If no response message is received until the timer T_RBP has expired, the MS 2 considers the most recently sent SDB frame has been lost and retransmits the same SDB frame. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases a power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message. FIGs. 8 and 9 illustrate an MS operation and a BS operation for the exchange of messages described referring to FIGs. 7A, 7B, and 7C. The MS operation in FIG. 8 is the same as that in FIG. 5 since the signal ACK or NACK is recognized by monitoring the response field 20 of a response message received from the BS 4. That is, steps 200 to 238 of FIG. 5 are almost identical to steps 400 to 438 of FIG. 8. The BS operation in FIG. 9 is different from that in FIG. 6 in that the step of sending the signal ACK is added because the signal ACK or NACK is sent for each received SDB frame. That is, a response message including the signal ACK and a marked received SDB sequence number is sent in step 511. As described above, the present invention advantageously minimizes a response time and increases transmission efficiency by enabling an RBP transmission of long burst data when a power control is performed on a designated - 19 - reverse common channel to appropriately control an initial system access power. While the RBP implementation is confined to the dormant state in the existing 3G IS-95, burst data can be continuously transmitted in the suspended state as well as in the dormant state without the need for the RLP which is implemented by assigning a control channel when transitioning from the dormant state or suspended state to the control hold state or active state. As a result, a response time and thus a transmission delay of data packet can be reduced. While the present invention has been described in detail with reference to the specific embodiments, they are mere exemplary applications. Thus, it is to be clearly understood that many variations can be made by anyone skilled in the art within the scope and spirit of the present invention. - 20 - WE CLAIM 1. A method of transmitting user data on a reverse common channel with a reverse dedicated channel released, comprising the steps of: designating the reverse common channel to the reverse dedicated channel; dividing user data into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel; transmitting the plurality of segmented messages in the data segments of consecutive frames on the designated reverse common channel; and determining whether a base station receives each of the segmented messages. 2. The method as claimed in claim 1, wherein the reverse common channel is a power-controlled logical dedicated channel. 3. The method as claimed in claim 2, wherein each of the consecutive frames has a segmented message, a sequence number corresponding to the segmented message, and information indicating the presence or absence of a segmented message in a succeeding frame. 4. The method as claimed in claim 1, wherein the determining step comprises the step of receiving a response message from the base station indicating reception of each of the segmented messages. 5. The method as claimed in claim 4, wherein the response message comprises information indicating reception of a particular segmented message, and a sequence number identifying the particular segmented message. 21 6. The method as claimed in claim 1, wherein the determining step comprises the step of receiving a response message from the base station indicating a failed reception of a particular segmented message. 7. The method as claimed in claim 6, comprising the step of retransmitting, by the mobile station, at least the particular segmented message in response to the mobile station receiving the response message indicating a failed reception of the particular segmented message. 8. The method as claimed in claim 7, comprising the step of determining by the mobile station whether a response message indicating reception of the retransmitted segmented message is received from the base station. 9. The method as claimed in claim 8, comprising the step of determining whether the response message indicating reception of the retransmitted segmented message is received from the base station within a predetermined time period. 10. The method as claimed in claim 9, wherein the response message indicates reception of the retransmitted segmented message in the base station if the response message is received from the base station within the predetermined time period. 11. The method as claimed in claim 1, comprising the step of determining whether a response message indicating reception in the base station of a last segmented message is received from the base station. 12. The method as claimed in claim 11, comprising the step of determining whether the response message indicating reception of the last segmented message is received from the base station within a predetermined time period. 22 13. The method as claimed in claim 11, comprising the step of the base station retransmitting the last segmented message if the response message indicating reception of the last segmented message is not received from the base station within a predetermined time period. 14. The method as claimed in claim 11, comprising the step of the base station transmitting a succeeding segmented message based on receiving a response message from the base station if the received response message does not correspond to the response message indicating reception in the base station of the last segmented message. 15. A method of receiving a message via consecutive frames on a designated reverse common channel from a mobile station to a base station, where the message is segmented into a plurality of message segments and each of said consecutive frames includes a user data field on which one of the plurality of message segments is loaded, and a field indicating whether a following frame contains a message segment, said method comprising the steps of: checking the more flag field of each frame; checking CRCs (Cyclic Redundancy Codes) of each frame; and determining whether the totality of message segments transmitted via the consecutive frames are received at the base station by checking a count of the more flag field. 16. The method as claimed in claim 15, wherein the reverse common channel is a power-controlled logical dedicated channel. 23 17. The method as claimed in claim 15, comprising the step of transmitting a response message from the base station to the mobile station upon the base station receiving one of the plurality of message segments, said response message indicating reception of one of the plurality of message segments. 18. The method as claimed in claim 17, wherein the response message comprises information indicating reception of one of the plurality of message segments, and a sequence number of said one of the plurality of message segments. 19. The method as claimed in claim 17, comprising the step of making a second transmission request by the mobile station for one of the plurality of message segments, if said one of the plurality of message segments is not received by the mobile station within a predetermined time after reception of a previous message segment. 20. The method as claimed in claim 19, comprising the step of transmitting a response message, by the mobile station, indicating reception of the retransmitted one of the plurality of message segments to the mobile station, said response message being transmitted after a predetermined time from the transmission of the retransmission request. 21. The method as claimed in claim 15, comprising the step of sending a response message to the mobile station indicating reception of a last message segment of the plurality of message segments upon reception of the last message segment by the base station. 22. The method as claimed in claim 15, comprising the step of requesting retransmission of a message segment, by the base station, of said plurality of message segments, if said message segment has an error. 24 23. The method as claimed in claim 15, comprising the steps of: determining whether reception of the plurality of message segments has been completed by continuously checking the more flag fields; and 25 reassembling the received plurality of message segments when reception has been completed. A method is provided of continuously transmitting user data on a reverse common channel in a mobile communication system without a reverse dedicated channel. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. The plurality of segmented messages are then transmitted in the data segments of consecutive frames on the reverse common channel. The method further comprises determining whether a base station receives the segmented messages by receiving a response message indicating reception of the segmented messages. The common channel is preferably a power-controlled logical dedicated channel.

Full Text

CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application entitled METHOD OF CONTINUOUSLY TRANSMITTING PACKET DATA ON REVERSE COMMON CHANNEL IN MOBILE COMMUNICA TION SYSTEM
earlier filed in the Korean Industrial Property Office on 14 Apr. 1998, and there duly assigned Serial No. 98-14275.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a mobile communication system, and in particular, to the next generation mobile communication system for providing multimedia data services.
2. Description of the Related Art
The third generation (3G) IS-95 supports services for transmission of high quality voice, high speed data, and moving pictures, and internet browsing. In this mobile communication system, a forward link is directed from a base station (BS) to a mobile station (MS) and a reverse link is directed from the MS to the BS. A

paging channel and an access channel (referred to as reverse common channels) are used to transport data between a BS 4 and an MS 2 before a voice call set-up, as shown in FIG. 10. The BS 4 sends a message on the paging channel and receives a response message from the MS 2 on the access channel. The MS 2 sends a message on the access channel and receives a response message from the BS 4 on the paging channel. A plurality of paging channels and access channels are available for use. The paging channels are identified by Walsh codes and the access channels are identified by long codes.
The existing 3GIS-95 is well established for voice communication but fails to fully ensure an intended communication quality for packet data communication, though a large amount of packet data including a long burst period and an idle period is transmitted by an RLP (Radio Link Protocol) and short burst data is transmitted by an RBP (Radio Burst Protocol). RBP is the transmission scheme of determining whether to retransmit the same SDB (Short Data Burst) frame or to send another SDB frame depending on an acknowledgement signal ACK/negative acknowledgement signal NACK received for the previously sent SDB frame, in a dormant state of the 3G IS-95. Thus, the RBP transmission scheme is poor in terms of response time and gain rate, and shows a relatively low transmission efficiency because it is confined to a burst substate of the dormant state. Since the RBP is implemented on a reverse common channel, a response is delayed and reliability is low. In particular, the procedure of sending an SDB frame, receiving a response, and then sending another SDB frame causes a long delay time.
SUMMARY OF THE INVENTION
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It is an object of the present invention, therefore, to provide a method of continuously transmitting a long burst message on a reverse common channel. .
It is another object of the present invention to provide a method of implementing a full-duplex RBP transmission scheme in which an SDB message is continuously transmitted in a dormant state.
It is a further object of the present invention to provide a method of enabling a long-burst RBP transmission when a power control is performed on a designated reverse common channel to appropriately control an initial system access power, to thereby minimize a response time and increase transmission efficiency.
It is a still further object of the present invention to provide a method of continuously transmitting burst data without implementing an RLP by setting a control channel when transiting a dormant state or a suspended state to a control hold state or an active state.
To achieve the above objects, there is provided a method of transmitting user data on a reverse common channel with a reverse dedicated channel released. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. Then, the plurality of segmented messages are transmitted in the data segments of consecutive frames on the reverse common channel, and it is determined whether a base station receives the segmented messages.
BRIEF DESCRIPTION OF THE/DRAWINGS
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The above objects and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
FIG. 1A is a flowchart of transmitting an SDB message from an MS on a reverse common channel in a burst substate of a dormant state, as proposed in the existing 3GIS-95;
FIG. 1B is a flowchart of receiving an SDB message in a BS on a reverse common channel in a burst substate of a dormant state, as proposed in the existing 3G IS-95;
FIG. 2 illustrates the exchange of messages between the BS and the MS of FIGs. 1A and 1B;
FIG. 3A illustrates the structure of an SDB frame in a continuous RBP transmission scheme according to an embodiment of the present invention;
FIG. 3B illustrates the structure of a response frame for a received message in the continuous RBP transmission scheme according to the embodiment of the present invention;
FIG. 4A illustrates the exchange of messages and an error correcting operation upon generation of a negative acknowledgement signal NACK in a first embodiment of the continuous RBP transmission scheme in which the negative acknowledgement signal NACK is transmitted only for an error-having SDB frame;
FIG. 4B illustrates the exchange of messages and an error correcting operation upon loss of a negative acknowledgement signal NACK in the first embodiment of the continuous RBP transmission scheme;
FIG. 4C illustrates the exchange of messages and an error correcting operation upon loss of an MS initiated SDB frame in the first embodiment of the
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continuous RBP transmission scheme;
FIG. 5 is a flowchart of an MS operation in the first embodiment of the continuous RBP transmission scheme;
FIG. 6 is a flowchart of a BS operation in the first embodiment of the continuous RBP transmission scheme;
FIG. 7A illustrates the exchange of messages and an error correcting operation upon generation of a negative acknowledgement signal NACK in a second embodiment of the continuous RBP transmission scheme in which a response signal ACK or NACK is transmitted for each received SDB frame;
FIG. 7B illustrates the exchange of messages and an error correcting operation upon loss of a response signal ACK or NACK in the second embodiment of the continuous RBP transmission scheme;
FIG. 7C illustrates the exchange of messages and an error correcting operation upon loss of an MS initiated SDB frame in the second embodiment of the continuous RBP transmission scheme;
FIG. 8 is a flowchart of an MS operation in the second embodiment of the continuous RBP transmission scheme;
FIG. 9 is a flowchart of a BS operation in the second embodiment of the continuous RBP transmission scheme;
FIG. 10 is a view of channels used by the BS and the MS before a voice call set-up; and
FIG. 11 is a view of packet service (MAC) states in a communication system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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Preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Like reference numerals denote the same components in the drawings. It is to be noted that a detailed description of the well-known function or structure of the present invention will be omitted if it is deemed to obscure the subject matter of the present invention.
For better understanding of the present invention, packet service states in a communication system will be described referring to FIG. 11. As shown, a packet service is composed of packet null state, initialization state, active state, control hold state, suspended state, dormant state, and reconnect state. Packet service options are connected in the control hold state, active state, and suspended state. The packet null state refers to a default state prior to activation of the packet service.
Upon request for a packet service in the packet null state, a connection to the packet service is attempted in the initialization state. When a dedicated control channel (DCCH) is set, the initialization state transitions to the control hold state. The DCCH is needed to initialize an RLP and a PPP (Point-to-Point Protocol). In the active state, forward and reverse DCCHs and dedicated traffic channels DTCHs) are maintained and RLP frames are exchanged on the channels. When a relatively short inactive period is produced, the packet service enters the suspended state to efficiently use the radio resources and reduce power consumption of the MS. While the DCCHs are released in the suspended state, both the BS and MS reserve the information of RLP status, traffic channel assignment, encryption variables, and the like and thus can relatively easily be assigned the DCCHs. In the suspended state, the MS monitors a forward packet paging channel. Upon
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designation of a DCCH, the suspended state transitions to the control hold state. If a packet is not received for a predetermined time in the suspended state, the dormant state is entered. The dormant state is composed of an idle substate and a burst substate and refers to the state where packet service options, control and traffic channels, and the RLP are released, with only the PPP maintained. The dormant state transitions to the packet null state if the PPP is released.
FIGs. 1A and 1B are flowcharts of an MS operation for transmitting an SDB message and a BS operation for receiving the SDB message on a reverse common channel in the burst substate of the dormant state in the existing 3G IS-95. After the MS 2 sends an SDB frame on a reverse common channel (i.e., access channel), reception of an acknowledgement signal ACK from the BS 4 on a paging channel indicates a successful transmission, but reception of a negative acknowledgement signal NACK or failure to receive a response message from the BS 4 for a predetermined time, that is, until a timer T_RBP has expired, indicates a failed transmission. The BS 4 checks the CRC (Cyclic Redundancy Code) of the SDB frame received on the reverse common channel (access channel) and sends the acknowledgement signal ACK or the negative acknowledgement signal NACK on the paging channel.
Referring to FIGs. 1A and 1B, the MS 2 sends an SDB frame on a reverse common channel and sets the timer T_RBP in step 100. The BS 4 determines whether the SDB frame is received on the reverse common channel in step 112. If it is, the BS 4 checks the CRC of the SDB frame in step 114 and determines the presence or absence of errors in the SDB frame in step 116. If no CRC errors were generated, the BS 4 sends the MS 2 the acknowledgement signal ACK indicating
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a successful transmission on the paging channel, in step 118. If CRC errors were found, the BS 4 sends the MS 2 the negative acknowledgement signal NACK or a message indicating a failed transmission in step 120.
The MS 2 determines whether the signals ACK or NACK are received before the timer T_RBP has expired, in steps 102 and 104. Upon receipt of the signal ACK, the MS 2 determines whether there is another SDB frame to send in step 106. If there is, the procedure returns to step 100. Otherwise, the procedure ends.
If the signal NACK or the message indicating a failed transmission are received before the timer T_RBP has expired, or if none of the signals ACK and NACK, and the message indicating a failed transmission are received until the timer T_RBP has expired in steps 102 and 104, the MS 2 retransmits the same SDB frame and resets the timer T_RBP in step 110. Then, the procedure goes back to step 102.
FIG. 2 is a flowchart illustrating the exchange of messages between the BS 2 and the MS 4 of FIGs. 1A and 1B on the basis of the protocol.
An embodiment of the present invention is directed to transmission of a long burst message by modifying the RBP transmission scheme described referring to FIGs. 1A, 1B, and 2 in the existing 3GIS-95. To do so, designation of a common channel and power control of the designated common channel should precede.
A well-recognized example of the common channel designation is disclosed

in Korea Application No. 1998-13149 filed on 13 April, 1998 and entitled "Device and Method for Transmitting Common Channel Message in CDMA Communication System" by Ki-Sung JUNG, et. al.. A detailed description of power control of a designated channel can be found in Korea Application No. 1998-14276 filed on 14 April, 1998 and entitled "Power Control of Reverse Common Channel in CDMA Communication System" by Jin-Woo CHOI, et. al..
The designation of a common channel (see Korea Application No. 1998-13149) refers to the process of designating a reverse common channel as dedicated (hereinafter, designated common channel) in a logical sense of the term when a message longer than one frame is generated in order to continuously transmit the long message. More specifically, upon generation of a message to send, the MS 2 determines whether the message can be sent at one time. If it can be, the conventional RBP transmission scheme is used. Otherwise, the long message is divided into frame segments, and a more message flag and a designation request flag of a frame message are set prior to transmission to the BS 4. Upon receipt of the frame message, the BS 4 monitors the more message flag and the designation request flag. If they are cleared, the BS 4 clears a designation flag and sends an acknowledgement to the MS 2. If either of the more flag message and the designation request flag is set, the BS 4 determines whether there is a channel to designate and if there is, it designates the channel. The BS 4 sets a maximum duration and a priority for the designated channel when necessary, and sends the acknowledgement message to the MS 2.
Now turning to the power control of the designated channel (see Korea Patent No. 1998-14276), since the BS 4 receives SDB frames continuously, a
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message sent by the BS 4 should include information on the above-described channel designation and whether to perform a power control, and the Walsh code number of a common power control channel and the location (i.e., slot index) of a power control signal if the power control is performed. A predetermined time after the BS 4 sends a response message for the designated channel request to the MS 2, it sends a power control signal in. a predefined slot on a power control dedicated channel at predetermined intervals. Then, the MS 2 sends preambles on the channel designated by the response message for a predetermined time and adjusts transmit power between the BS 4 and the MS 2. The MS 2 sends a transmit message to the BS 4 on the designated common channel a predetermined time later. While the BS 4 receives the message from the MS 2, it continuously controls power by sending the power control signal on the common power control channel.
An RBP for continuous SDB message transmission can be implemented in the embodiments of the present invention if the afore-described channel requirements of common channel designation and power control of a designated channel are satisfied.
Implementation of the RBP for continuous SDB frame transmission according to the embodiments of the present invention requires an SDB frame shown in FIG. 3A and a response frame for a received message, shown in FIG. 3B. The SDB frame and the response frame are sent by the MS 2 and the BS 4, respectively.
In FIG. 3A, the SDB frame is comprised of an SDB user data field 10, a
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transmitted SDB sequence field 12, and a more flag field 14. The transmitted SDB sequence field 12 provides the sequence number of an SDB frame to be continuously transmitted from the MS 2, and the more flag field 14 indicates whether there is an SDB frame following the current SDB frame. In FIG. 3B, the response frame is comprised of a response field 20 and a received SDB sequence field 22. The response field 20 informs the MS 2 of the presence or absence of errors in a received message by the signal ACK or NACK. The received SDB sequence field 22 provides the sequence number of the currently received SDB frame. The transmitted and received SDB sequence fields 12 and 22 contain the same bits.
An SDB message is transmitted continuously in two ways depending on a response from the BS 4: the signal NACK is sent only if the BS 4 detects errors; and the signal ACK or NACK is sent for each SDB frame received from the MS
FIGs. 4A to 6 illustrate the first embodiment of the continuous RBP transmission scheme according to the present invention, and FIGs. 7A to 9 illustrate the second embodiment of the continuous RBP transmission scheme.
FIG. 4A is a flowchart of a message transmission/reception and an error correcting operation upon receipt of the signal NACK in the first embodiment of the RBP transmission scheme where the signal NACK is transmitted only for an error-having SDB frame. The MS 2 receives a response message shown in FIG. 3B from the BS 4 while the MS 2 sends SDB frames continuously on a power-controlled designated common channel. Upon receipt of the response message
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including the signal NACK, the MS 2 detects an error-having SDB frame by checking the received SDB sequence field 22 of the response message and retransmits the corresponding SDB frame. When the continuous RBP transmission procedure is completed, the BS 4 releases the power-controlled designated common channel and then reassembles received SDB frames based on an SDB sequence to construct a complete SDB message.
FIG. 4B is a flowchart of an error correcting operation when the MS 2 fails to receive the signal NACK due to characteristics inherent to a radio environment. If an SDB frame received from the MS 2 has errors, the BS 4 sends a response message having the signal NACK and a corresponding received SDB sequence number, and sets a timer T_NACK. If the SDB frame corresponding to the received SDB sequence number is not received from the MS 2 until the timer T_NACK has expired, the BS 4 considers the signal NACK to have been lost and retransmits the signal NACK. The MS 2 considers the SDB frame successfully transmitted since it does not receive the signal NACK, and retransmits the SDB frame corresponding to the received SDB sequence number of the NACK response message only when it receives the signal NACK from the BS 4. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and then reassembles the received SDB frames based on an SDB sequence to construct a complete SDB message.
FIG. 4C illustrates an error correcting operation when an MS initiated SDB frame is lost, during transmission. The BS 4 receives an SDB frame and checks the more flag field 14 of the SDB frame. If the more flag field 14 is set, the BS 4 sets
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a timer T_SDB and awaits the next SDB frame from the MS 2. If the BS 4 does not receive the next SDB frame until the timer T_SDB has expired, the BS 4 sends the MS 2 a response message with the response field set to NACK and the received SDB sequence field set to a sequence number following the transmitted SDB sequence number of the most recently received SDB frame which was MS initiated for the first time. The MS 2 considers the transmission of its initiated message successful until it receives the signal NACK. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and then reassembles received SDB frames based on an SDB sequence to construct a complete SDB message.
FIGs. 5 and 6 are flowcharts of an MS operation and a BS operation for a message communication described referring to FIGs. 4A, 4B, and 4C. FIG. 5 is a flowchart of the MS operation in the first embodiment of the continuous RBP transmission scheme, and FIG. 6 is a flowchart of the BS operation in the first embodiment of the continuous RBP transmission scheme.
Referring to FIGs. 5 and 6, upon generation of an SDB message to send in step 200 of FIG. 5, the MS 2 determines whether the SDB message contains two or more frames in step 202. If the SDB message is one frame, the SDB message is sent to the BS 4 in the conventional RBP transmission scheme. If the SDB message should be sent in two ore more frames, the MS 2 requests assigmnent of a designated common channel from the BS 4 in step 206.
Upon receipt of the request for a designated common channel in step 300 of FIG. 6, the BS 4 determines whether there is an available designated common
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channel in step 302. If the request is not acknowledgeable, the BS 4 sends the MS 2 a message having a designation flag cleared in step 304. If it is acknowledgeable, the BS 4 assigns a power-controlled designated common channel and sends a message having a designation flag set to the MS 2, in step 306.
The MS 2 determines whether the designation flag of the received message is set, in step 208. If it is not, the MS 2 resumes the request for a designated common channel in step 206. If it is, the MS 2 divides the SDB message into frame segments in step 210. The SDB segments are SDB user data recorded in the SDB user data field 10 shown in FIG. 3A. In step 212, the MS 2 sets the more flag field 14 and marks an SDB sequence number on the transmitted SDB sequence field 12. If the last SDB segment is to be sent, the more flag field 14 is reset. The MS 2 determines whether a response message is received from the BS 4, in step 214. When no response message is received, the MS 2 sends an SDB frame including the marked more flag and transmitted SDB sequence number and the SDB user data to the BS 4 on the power-controlled designated common channel in step 216. Then, the MS 2 determines whether the currently sent SDB frame is the last one, in step 218. If it is not, the procedure returns to step 210.
Meanwhile, the BS 4 determines whether the SDB frame is received in step 308. Upon receipt of the SDB frame, the BS 4 checks the CRC of the SDB frame and determines whether it has an error in step 310. If there are no errors, the BS 4 determines whether the received SDB frame was retransmitted by the MS 2 for the signal NACK, in step 312. If it is transmitted for the first time, the BS 4 determines whether the more flag of the SDB frame is set, in step 316. If the more flag is set, the BS 4 sets the timer T SDB to correct errors if a following SDB frame is not
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received, in step 318. If the more flag is not set, the procedure goes to step 310. In step 328, the BS 4 determines whether the timer T_NACK has expired. The timer T_NACK is set to send the signal NACK from the BS 4 and thus not used when an SDB frame is normally received. If the timer T_NACK has not expired, the BS 4 goes back to step 308.
In accordance with the embodiment of the present invention, the BS 4 sends no response message if an SDB frame is successfully received. For example, FIG. 4A shows that the BS 4 sends no response message for the successfully received SDB frames (1), (2), and (4). Here, (1), (2), and (4) denote the sequence numbers of the SDB frames.
Returning to FIG. 6, if a CRC error is found in the received SDB frame in step 310, the BS 4 sends the signal NACK to the MS 2 in step 320. That is, the sequence number of the error-having SDB frame is marked on the received SDB sequence field 22 of FIG. 3B and the signal NACK is marked on the response field 20. By way of example, if the SDB frame (3) has errors, the BS 4 sends a response message containing the signal NACK (3) in FIG. 4A. The BS 4 sets the timer T_NACK in step 322 to correct errors when the signal NACK is not reliably sent to the MS 2 as shown in FIG. 4B.
Upon receipt of the response message including the signal NACK (3) from the BS 4, the MS 2 checks the received SDB sequence field 22 of the response message in step 221. The MS 2 retransmits the SDB frame (SDB frame (3) in FIG. 4A) corresponding to the sequence number in step 222. It is optional for the BS 4 to send a signal ACK(3) for the retransmitted SDB frame (3) to the MS 2, and for
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the MS 2 to determine whether the signal ACK(3) is received until the timer T_RBP has expired. For example, even if the BS 4 sends no response message for the retransmitted SDB frame (3) until the timer T RBP has expired, the MS 2 considers the transmission successful.
If the MS 2 fails to receive the response message including the signal NACK(3), the MS 2 considers the previous SDB frame transmission successful and sends the next SBD frame to the BS 4. If the SDB frame for which the signal NACK is generated is not received until the timer T_NACK has expired in steps 308 and 328; the BS 4 retransmits the signal NACK to the MS 2, in step 330. Then, the BS 4 resets the timer T_NACK in step 332. From FIG. 4B, it is noted that the BS 4 resends the signal NACK (3) to the MS 2 when the timer T_NACK has expired.
Meanwhile, if the BS 4 fails to receive an SDB frame until the timer T_SDB has expired in steps 308 and 324, it sends the MS 2 a response message having the signal NACK and a sequence number following the most recently received SDB frame which was transmitted from the MS 2 for the first time marked on the received SDB sequence field 22, in step 326. The BS 4 sets the timer T_SDB in step 318 and goes to step 328. Referring to FIG. 4C, when the timer T_SDB has expired, the BS 4 sends a signal NACK(4) corresponding to the sequence number (4) following the most recently received SDB frame (3).
In step 218 of FIG. 5, the MS 2 determines whether a current SDB frame is the last one, and in step 224, it sets the timer T_RBP. Then, the MS 2 determines whether a response message is received from the BS 4 in step 226.
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On the other hand, if the BS 4 receives the last SDB frame (more flag reset) in step 314, it sends a response message including the signal ACK indicating completed reception to the MS 2 in step 334. The BS 4 releases the power-controlled designated common channel in step 336, and reassembles received SDB frames to construct a complete SDB message in step 338.
If the MS 2 fails to receive a response message until the timer T_RBP has expired in steps 226 and 227, it retransmits the most recently sent SDB frame in step 238. Upon receipt of the response message, the MS 2 determines whether the response field 20 of the response message indicates an acknowledgement in step 236. In the case of a negative acknowledgement, the MS 2 retransmits the most recently sent SDB frame in step 238.
If a message received within the duration of the timer T_RBP is not a response message for the most recently sent message in steps 226 and 228, the MS determines whether the response field 20 of the response message is set to ACK in step 230. If the response field 20 is set to NACK, the MS 2 detects the sequence number from the received SDB sequence field 20 of the response message and retransmits the SDB frame corresponding to the detected sequence number to the BS 4, in step 234.
Then, a description of the second embodiment of the RBP transmission scheme where a signal ACK or NACK is generated for each SDB frame received from the MS 2 will be given referring to FIGs 3A and 3B, FIGs. 7A, 7B, and 7C, and FIGs. 8 and 9.
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FIG. 7A illustrates a message communication and an error correcting operation upon generation of the signal NACK in the second embodiment of the RBP transmission scheme where the signal ACK is generated for an error-free SDB frame and the signal NACK is generated for an error-having SDB frame. The MS 2 receives a response message from the BS 4 while continuously transmitting SDB frames on a power-controlled designated common channel. If the response message contains the signal NACK, the MS 2 detects an error-having SDB frame by checking the received SDB sequence field 22 of the response message and retransmits the corresponding SDB frame. When the continuous RBP transmission scheme is completed, the BS 4 releases the power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message.
FIG. 7B illustrates an error correcting operation when the MS 2 fails to receive a response signal ACK or NACK from the BS 4 due to characteristics inherent to a radio environment. The MS 2 sends an SDB frame and sets the timer T_RBP. If the signal ACK or NACK with the sequence number of the sent SDB frame is not received until the timer T_RBP has expired, the MS 2 considers that the SDB frame has errors and retransmits the SDB frame. Alternatively, the MS 2 determines whether to retransmit the SDB frame by setting the timer T_ACK to check a response from the BS 4. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases the power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message.
FIG. 7C illustrates an error correcting operation when an MS initiated SDB
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frame is lost during transmission. The BS 4 receives an SDB frame and monitors the more flag field 14 of the SDB frame. If the more flag is set, the BS 4 sets the timer T_SDB and awaits the next SDB frame from the MS 2. If no SDB frame is received until the timer T SDB has expired, the BS 4 sends the MS 2 a response message including the signal NACK and the sequence number following the transmitted sequence number of the most recently received SDB frame. This error correction can be performed in the MS 2. If no response message is received until the timer T_RBP has expired, the MS 2 considers the most recently sent SDB frame has been lost and retransmits the same SDB frame. When the continuous RBP transmission scheme is completed in this manner, the BS 4 releases a power-controlled designated common channel and reassembles received SDB frames based on an SDB sequence to construct a complete SDB message.
FIGs. 8 and 9 illustrate an MS operation and a BS operation for the exchange of messages described referring to FIGs. 7A, 7B, and 7C. The MS operation in FIG. 8 is the same as that in FIG. 5 since the signal ACK or NACK is recognized by monitoring the response field 20 of a response message received from the BS 4. That is, steps 200 to 238 of FIG. 5 are almost identical to steps 400 to 438 of FIG. 8. The BS operation in FIG. 9 is different from that in FIG. 6 in that the step of sending the signal ACK is added because the signal ACK or NACK is sent for each received SDB frame. That is, a response message including the signal ACK and a marked received SDB sequence number is sent in step 511.
As described above, the present invention advantageously minimizes a response time and increases transmission efficiency by enabling an RBP transmission of long burst data when a power control is performed on a designated
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reverse common channel to appropriately control an initial system access power. While the RBP implementation is confined to the dormant state in the existing 3G IS-95, burst data can be continuously transmitted in the suspended state as well as in the dormant state without the need for the RLP which is implemented by assigning a control channel when transitioning from the dormant state or suspended state to the control hold state or active state. As a result, a response time and thus a transmission delay of data packet can be reduced.
While the present invention has been described in detail with reference to the specific embodiments, they are mere exemplary applications. Thus, it is to be clearly understood that many variations can be made by anyone skilled in the art within the scope and spirit of the present invention.
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WE CLAIM
1. A method of transmitting user data on a reverse common channel with a
reverse dedicated channel released, comprising the steps of:
designating the reverse common channel to the reverse dedicated channel;
dividing user data into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel;
transmitting the plurality of segmented messages in the data segments of consecutive frames on the designated reverse common channel; and
determining whether a base station receives each of the segmented messages.
2. The method as claimed in claim 1, wherein the reverse common channel is a
power-controlled logical dedicated channel.
3. The method as claimed in claim 2, wherein each of the consecutive frames
has a segmented message, a sequence number corresponding to the segmented
message, and information indicating the presence or absence of a segmented
message in a succeeding frame.
4. The method as claimed in claim 1, wherein the determining step comprises
the step of receiving a response message from the base station indicating
reception of each of the segmented messages.
5. The method as claimed in claim 4, wherein the response message comprises
information indicating reception of a particular segmented message, and a
sequence number identifying the particular segmented message.
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6. The method as claimed in claim 1, wherein the determining step comprises
the step of receiving a response message from the base station indicating a
failed reception of a particular segmented message.
7. The method as claimed in claim 6, comprising the step of retransmitting, by
the mobile station, at least the particular segmented message in response to the
mobile station receiving the response message indicating a failed reception of
the particular segmented message.
8. The method as claimed in claim 7, comprising the step of determining by the
mobile station whether a response message indicating reception of the
retransmitted segmented message is received from the base station.
9. The method as claimed in claim 8, comprising the step of determining
whether the response message indicating reception of the retransmitted
segmented message is received from the base station within a predetermined
time period.
10. The method as claimed in claim 9, wherein the response message indicates
reception of the retransmitted segmented message in the base station if the
response message is received from the base station within the predetermined
time period.
11. The method as claimed in claim 1, comprising the step of determining
whether a response message indicating reception in the base station of a last
segmented message is received from the base station.
12. The method as claimed in claim 11, comprising the step of determining
whether the response message indicating reception of the last segmented
message is received from the base station within a predetermined time period.
22

13. The method as claimed in claim 11, comprising the step of the base station
retransmitting the last segmented message if the response message indicating
reception of the last segmented message is not received from the base station
within a predetermined time period.
14. The method as claimed in claim 11, comprising the step of the base station
transmitting a succeeding segmented message based on receiving a response
message from the base station if the received response message does not
correspond to the response message indicating reception in the base station of
the last segmented message.
15. A method of receiving a message via consecutive frames on a designated
reverse common channel from a mobile station to a base station, where the
message is segmented into a plurality of message segments and each of said
consecutive frames includes a user data field on which one of the plurality of
message segments is loaded, and a field indicating whether a following frame
contains a message segment, said method comprising the steps of:
checking the more flag field of each frame;
checking CRCs (Cyclic Redundancy Codes) of each frame; and
determining whether the totality of message segments transmitted via the consecutive frames are received at the base station by checking a count of the more flag field.
16. The method as claimed in claim 15, wherein the reverse common channel is
a power-controlled logical dedicated channel.
23

17. The method as claimed in claim 15, comprising the step of transmitting a
response message from the base station to the mobile station upon the base
station receiving one of the plurality of message segments, said response
message indicating reception of one of the plurality of message segments.
18. The method as claimed in claim 17, wherein the response message
comprises information indicating reception of one of the plurality of message
segments, and a sequence number of said one of the plurality of message
segments.
19. The method as claimed in claim 17, comprising the step of making a second
transmission request by the mobile station for one of the plurality of message
segments, if said one of the plurality of message segments is not received by the
mobile station within a predetermined time after reception of a previous message
segment.
20. The method as claimed in claim 19, comprising the step of transmitting a
response message, by the mobile station, indicating reception of the
retransmitted one of the plurality of message segments to the mobile station,
said response message being transmitted after a predetermined time from the
transmission of the retransmission request.
21. The method as claimed in claim 15, comprising the step of sending a
response message to the mobile station indicating reception of a last message
segment of the plurality of message segments upon reception of the last
message segment by the base station.
22. The method as claimed in claim 15, comprising the step of requesting
retransmission of a message segment, by the base station, of said plurality of
message segments, if said message segment has an error.
24

23. The method as claimed in claim 15, comprising the steps of:
determining whether reception of the plurality of message segments has been completed by continuously checking the more flag fields; and
25
reassembling the received plurality of message segments when reception has been completed.
A method is provided of continuously transmitting user data on a reverse common channel in a mobile communication system without a reverse dedicated channel. The user data is divided into a plurality of segmented messages if the user data is longer than a data segment in a frame of the reverse common channel. The plurality of segmented messages are then transmitted in the data segments of consecutive frames on the reverse common channel. The method further comprises determining whether a base station receives the segmented messages by receiving a response message indicating reception of the segmented messages. The common channel is preferably a power-controlled logical dedicated channel.

Documents:

00340-cal-1999 abstract.pdf

00340-cal-1999 claims.pdf

00340-cal-1999 correspondence.pdf

00340-cal-1999 description(complete).pdf

00340-cal-1999 drawings.pdf

00340-cal-1999 form-1.pdf

00340-cal-1999 form-18.pdf

00340-cal-1999 form-2.pdf

00340-cal-1999 form-3.pdf

00340-cal-1999 form-5.pdf

00340-cal-1999 g.p.a.pdf

00340-cal-1999 letters patent.pdf

00340-cal-1999 priority document others.pdf

00340-cal-1999 priority document.pdf

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Patent Number

206847

Indian Patent Application Number

340/CAL/1999

PG Journal Number

20/2007

Publication Date

18-May-2007

Grant Date

15-May-2007

Date of Filing

13-Apr-1999

Name of Patentee

SAMSUNG ELECTRONUICS CO. LTD.,

Applicant Address

416, MAETAN-DONG,PALDAL-GU, SUWON-CITY, KYUNGKI-DO,

Inventors:

#	Inventor's Name	Inventor's Address
1	CHANG-HOI GU,	124 IMAE-DONG, PUNTANG-GU, SONGNAM-SHI, KYONGGI-DO,
2	JAE-MIN AHN,	PULEUN SAMHO APT 109-303, IRWONPON-DONG, KANGNAM-GU, SEOUL
3	SOON-YOUNG YOON,,	165, KARAK-DONG, SONGPA-GU, SEOUL,
4	KI-SUNG JUNG,	404-2, gugal-ri, kiheung-eup, yongin-shi, kyunggi-do,
5	HYUN-SUK LEE,	JUNGONG, APT, 4 DANJI, 420-106 CHAMSHIL 3 -DONG, SONGPA-GU, SEOUL,

PCT International Classification Number

H04B 7/212

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	14275/1998	1998-04-14	Republic of Korea