Title of Invention

A METHOD AND A SYSTEM FOR IMPLEMENTING A RADIO LINK PROTOCOL FOR A TRANSACTION ORIENTED PACKET DATACOMMUNICATION SYSTEM

Abstract A system and method of implementing a radio link protocol and dynamic partial echo management for a transaction oriented packet data communication system. A data backlog is described with a media access control layer controller and transmitting a BEGIN protocol data unit transmitted to a receiver. A media access control layer transaction is initiated in response to the transmitting of the BEGIN frame.
Full Text

Background Of The Invention
This invention relates to link and media access layer transaction initiation procedures in a communication system, and more particularly, to such procedures in time slotted communication systems.
Link layer recovery protocols are used for error and loss recovery in data communication systems. Link layer ref every Is especially crucial for wireless communications due to the particularly harsh loss and error characteristics of the link.
Typically, a link layer recovery protocol is initialized at the time of connection establishment. Also, in the case of data link protocols for cellular communications, the radio link protocol (RLP) is not implemented at the base station but typically situated back in the network so that data flows across the connection seamlessly as the mobile traverses multiple cells (across multiple handoffs). When a connection is established, the network typically assigns a unique temporary identifier which may be associated with a data link connection to a specific mobile station. For example in Cellular Digital Packet Service (CDPD), the Mobile Data link Protocol (MDLP) is established at packet data registration, and a Temporary Equipment Identifier (TEI) is assigned to the mobile station. The TEI is used by peer data link layer entities for subsequent data transfer.
Packet data transactions tend to be burst with possibly long periods of inactivity between transactions. For mobile stations involved in intermittent transactions, with long inter-transaction times (even though each transaction may involve significant data transfer), maintaining RLP back in the network has the following disadvantages: maintaining the RLP state information across long idle periods is a very inefficient use of network resources;

moving tiie RLP back into the network has an adverse impact on performance due to increased round trip delay; moving the RLP back into the network makes it harder to use adaptive modulation and incremental redundancy schemes, that can have a significant throughput advantage; maintaining a unique identifier across long idle periods is very inefficient and requires the use of a large identifier field (for example the TEI in CDPD); and using identifiers in each Medium Access control (MAC) layer transmission is desirable to avoid ambiguity, but long idratifiers are wasteful of RF bandwidth.
In a TDMA Digital Control Channel (DCCH), a 7 bit Partial Echo (PE) field has been used as a mobile station identifier. However, for users with intermittent packet transactions, there is significant probability of ambiguity with 7 bit PEs.
The present invention is directed to overcoming, or at least reducing, the effects of one or more of the problems set forth above.
Summary Of The Invention
In accordance wi the present invention, there is provided a system and mood of impetrating a radio link protocol and dynamic partial echo management for a transaction oriented packet data communication system. The method performs the steps of determining a data backlog with a media access control layer controller and transmitting a PDU to a receiver. The method further performs the step of initiating a media access control layer transaction in response to the transmitting of the BEGIN PDU.
Also in accordance wife the present invention, a system for implementing a radio link protocol (RLP) and dynamic partial echo management for a transaction oriented packet data system. The system con:^)rises a media access control layer controller for determining a data backlog in a media access control layer buffer and a media access control layer transmitter for transmitting a BEGIN Protocol Data Unit to a receiver. The system also includes a means for initiating a media access control layer transaction in response to the transmitting of the BEGIN Protocol Data Unit.

These and other features and advantages of the present invention will become apparent from Ae following detailed description, the accompanying drawings and the upended claims.
Brief Description Of The Drawings
Fig. 1 shows a block diagram of a communication system illxxstrating the operation on a packet data channel in accordance with the invention;
Fig. 2 is a graph showing the probability of two or more active users having the same partial echo;
Fig. 3 is a block diagram illustrating an exemplary implementation of a Media Access Control (MAC) layer from tiie Layer 2 block in Fig. 1;
Fig. 4 is a block diagram describing the internal structure of a mobile station MAC transmission controller block shown in Fig. 3;
Fig. S is a state diagram describing a router process for the mobile station transmission controller described in Fig. 4;
Fig. 6 is a state diagram describing a transmit controller process of the mobile station transmission controller described in Fig. 4;
Fig. 7 is a state diagram describing another part of Ae transmit controller process of the mobile station transmission controller described in Fig. 4;
Fig. S is a state diagram describing another part of die transmit controller process of the mobile station transmission controller described in Fig. 4;
Fig. 9 is a state diagram describing another part of the transmit controller process of the mobile station transmission controller described in Fig. 4;
Fig. 10 is a state diagram describing a retrieve retransmit data blocks process performed by tfie transmit controller (TCTX) block of Fig. 4;

Fig. 11 is a state diagram illustrating a retrieve new data blocks process performed by the transmit controller (TCTX) block of Fig. 4;
Fig. 12 describes a construct Protocol Data Unit (PDU) process, a transmit (TxT) table, and a sub-channel controllers transmit (SCCxT) table used by the TCTX block of Fig.
4;
Fig. 13 illustrates a physical control field (PCF) process that is executed by the mobile station transmission controller described in Fig. 4;
Fig. 14 illustrates an automatic retransmission request (ARQ) status process that is executed by the mobile station transmission controller described in Fig. 4;
Fig. 15 is a state diagram illustrating a mobile station receive controller process preformed by the receiver controller block of Fig. 4 in the context of transaction initiation;
Fig. 16 is a state diagram illustrating a mobile station receive controller process preformed by the receiver controller block of Fig. 4 \^^le a fixed coding mode ARQ transaction is in progress;
Fig. 17 is a state diagram illustrating an update receive (Rx) state executed by the receive controller block of Fig. 4 vend a data block is received;
Fig. 18 is a state diagram illustrating a mobile station receive table, an initialize receive controller (TCRX) parameters process, and a BEGIN PDU process which are executed by the receive controller of Fig. 4;
Fig. 19 is a state diagram illustrating a mobile station channel access manager (CAM) block of Fig. 3;
Fig. 20 is a state diagram illustrating the choose transmit controller (TCy) process and send coded MAC_PDU process which are executed by the CAM block of Fig. 3;
Fig. 21 is a state diagram illustrating a mobile station sub*channel controller process (SCC) block of Fig. 3;

hig. 22 IS a state diagram liiutratmg a check estimation and extract coded MAC_PDU process that is executed by the SCC block of Fig. 3 on obtaining data from the physical layer of Fig. 3;
Fig. 23 shows a signal flow diagram for downlink BEGIN PDU handshake process between a base station (cell) and a mobile using a stop and wait procedure;
Fig. 24 is a signal flow diagram of the downlink BEGIN PDU handshake process between the cell and die mobile without using a stop and wait procedure;
Fig. 25 is a signal flow diagram for an uplink BEGIN PDU handshake process between a cell and mobile;
Fig. 26 is a signal flow diagram for an uplink BEGIN PDU handshake process between the cell and the mobile;
Fig. 27 is a signal flow diagram for a process of assigning an active mobile identity (AMI) on a downlink different from AMI suggested on the uplink; and
Fig. 28 is a flow diagram illustrating an AMI assigned on downlink that is the same as AMI suggested on the uplink.
Detailed Description
In describing tiie invention this application uses the media access control (MAC) layer assumptions duchy are based on the Open System Interconnections (OSI) model OSI is an internationally accepted frame work of standards for communication between different systems made by different vendors. Most of the dominant communication protocols used today have a structure based on the OSI model. The OSI model organizes the communication process into seven different categories and places these categories in layered sequence based on their relation to the user. Layer 7 through 4 deal with the end to end communication message source and the message destination. While Layers 3 through 1 deal wide network access.
Layer 1, the physical layer, deals with the physical means of sending data over lines i.e. the electrical, mechanical and functional control of data circuits. Layer 2, the data link

layer, deals with procedures and protocols for operating communication lines. Layer 3, the network layer, determines how data is transferred between computers and routing within and between individual networks.
It is appreciated that the packet data channel is capable of supporting multiple modulations. The MAC layer is provided with frames of Layer 3 and translates them into a byte stream using flag delimiters. A radio link protocol (RLP), also referred to as a retransmission link protocol, is used to transfer frames of Layer 2 between a cell and the mobile station and vice versa. The byte stream of Layer 3 is segmented into RLP frames, and a siding window retransmission scheme is used for in-sequence delivery and recovery.
MAC layer transaction preferably starts with the transmission of a BEGIN frame. On the uplink and downlink, the MAC layer converts tied frames of Layer 3 into a byte stream and packs Ae byte stream into a series of CONTINUE frames. The last new data burst of a transaction is transmitted using an END frame.
The BEGIN frame of each transaction is transmitted using 4-level modulation in a stop and wait mode to obtain an acknowledgment from the receiver. On reception of the BEGIN frame, the receiver initializes an RLP. The BEGIN frame is also used to initialize a partial echo (PE) for the transaction, and to specify the mode of operation for subsequent automatic retransmission request (ARQ) mode CONTINUE frames in that transaction.
There are two possible modes of operation for ARQ mode CONTINUE frames on the downlink and uplink. The first is incremental redundancy (mode 0) and the second is freed coding (mode 1). It is appreciated that both mode 0 and mode 1 operate wide either fixed modulation or adaptive modulation
ARQ checks for errors in transmitted data. The sender encodes an error-detection (check) field in the transmitted data based on the contents of &e message. The receiver then recalculates the check field and compares it with the check field received. If the check fields match, an ACK (acknowledgment) is transmitted to the sender. If both check fields do not match, anal (negative acknowledgment) is returned, and the sender retransmits the message.

For both uplink and downlink transmissions, bitmap feedback in the form of an ARQ status is provided. In addition, ACK/NAK feedback is provided on a per time slot basis for uplink transmissions.
Fig. 1 shows a high level block diagram of operation on the packet data channel 100 in accordance within the invention. A transaction oriented packet data communication system 105 is shown Layer 3 frames 110 are provided to the Layer 2, MAC Layer 115, at Ae transmitter 120 and are translated into a byte stream using flags for demarcation. This permits the MAC layer 115 to provide a unified transport mechanism for different Layer 3 protocols. This byte stream is segmented into RLP frames and assigned a frame sequence number (FSN). The FSN is not exphcitly transmitted as part of the RLP frame.
For higher in meatier mode. Layer 1125 data is mapped into symbols
chosen from a 4-level, 8-level or 16-level modulation based on knowledge of Layer 2 backlog
and channel quality feedback 130 from the receiver 135. The channel quality is measured in
C terms of the signal to interference plus noise ratio, - at the input to the decoder in the
Layer 2 block 140 via physical layer 145 at the receiver 135. The decoder 140 then outputs the Layer 3 frames 150.
The IS-136 Digital Control Channel uses a temporary mobile station identifier also called a Partial Echo (PE). The PE is assumed to be an abbreviated Mobile Station Identity (MSID), i.e., the last 7 bits of the MSID is treated as the PE. Due to this mechanism, there is a significant probability teat two or more active users would use the same PE, and that erroneous protocol states would result frequently due to inability of mobiles to resolve their PE's correctly.
In Fig. 2, this probability is shown as a function of the number users that are simultaneously active on die channel. In packet data applications (as opposed to voice or circuit data applications), it is quite possible to have ten or more active users at any given time sharing &e same channel. In these cases, the probability of partial echo duplication reaches 25% and higher which is unacceptable for proper system operation.

The problem is selectively solved by assigning a proposed PE value (such as a dynamic PE) or an active mobile identity (AMI), to every mobile for all downlink transactions, and for uplink transactions which require more than a single burst. Both the downlink and uplink transactions are part of a MAC layer transaction. The AMI serves as a unique (assigned) local identifier to be used by the transmitter and the receiver for the duration of the transaction on a particular packet data channel. A new AMI is assigned for each new transaction &us eliminating the potential for ambiguity. The same AMI may be used in either direction (i.e., the AMI assignment is initiated by the uplink or downlink transaction, cheer begins first, and remains assigned till the end of data transfer in both directions).
A new transaction is initiated vend a transmission opportunity is identified and if the transmit buffer contains new data Downlink transactions may be ACK or NAK but uplink transactions are always ACK. Preferably every MAC layer transaction starts within a BEGIN Protocol Data Unit (PDU) handshake and proceeds with the transmission of a series of CONTINUE PDUs. The BEGIN PDU contains the proposed partial echo value and/or proposed mode of operation. ARQ mode CONTINUE PDUs may be transmitted in Incremental redundancy Mode (mode 0) or Fixed coding Mode (mode 1), and ARQ procedures for the two modes are different. Supervisory ARQ Status PDUs are used to provide Ae transmitter with periodic feedback of the receiver state.
The BEGIN PDU handshake (i.e., ACK transfer of the BEGIN PDU) establishes the AMI and Ae mode of operation for subsequent CONTINUE PDUs. It is appreciated that on multi-rate channels, it may also selectively be used to carry out phase assignment.
Base stations (also know as cells) selectively initiate downlink transactions through the transmission of a BEGIN PDU. The parameters indicated by the BEGIN PDU include: a Mobile Station Identity (MSID); an ARQ Mode (AM) indicating ether the transaction is ACK or NAK; a Poll Indicator (PI) for ACK transactions indicating vetches the mobile station is required to provide an ACK via an ARQ Status PDU; an AMI value to be assigned to tie mobile station; a Mode Indicator (MI) indicating whether the mode of operation for subsequent downlink CONTINUE PDUs is Fixed Coding or Incremental Redundancy and a

Phase Assignment (PA) indicating the phase for the transfer of subsequent data on the uplink or downlink.
If an AMI has already been assigned to the mobile station, the base station assigns the same AMI value within the BEGIN PDU. If the mobile station does not have a valid AMI, the base station randomly chooses an AMI value from the set of allowable values and assigns it to the mobile station using the BEGIN PDU. The base station Transmit Controller initializes a RLP in the indicated mode (IR or FC) on transmission of the BEGIN PDU. The mobile station receive controller initializes a peer RLP in the assigned mode on receipt of the BEGIN PDU.
Fig. 3 illustrates an example implementation of tie Media Access Control (MAC) 155 Layer in a duplex wireless data communication system. The MAC 155 interfaces with Layer 3 160 (network layer), physical layer (Layer 1) 165 (which includes a MAC layer transmitter 166 and MAC layer receiver 167) and with the management entity 170. In this example, the MAC 155 provides data and expedited control delivery services to Layer 3 160 and other higher layer entities. The MAC 155 uses Layer 1 165, via the MAC layer transmitter 166, for delivery of its PDUs over a radio interface 175. The management entity 170 initializes, terminates, suspends, resumes and configures MAC 155 operation. The management entity 170 also monitors tiie MAC 155 for errors. The management entity 170 also provides dynamic PE management for the transaction oriented packet data communication system 105, Fig. 1. The MAC 155 includes two Service Access Points (SAPs): SAPl for regular data and SAPO for expedited data and control. Each SAP has a corresponding transmit buffer (TXB), segmented (SGM), dosimeter (DSGM), frame extractor (FRX) and transmission controller (TC). A chaimel access manager (CAM) 180 multiplexes tie PDUs from the different transmission controllers (also known as ARQ engine) TCO and TCI, Fig. 3, and provides priority scheduling. The CAM 180 is also responsible for uplink random access, A MAC subchannel controllers (SCC) 185, preferably up to 9 (SCCO Rough SCC8), control transmission over each of the wireless data subchannels. The MAC Layer Controller (MLC) 190 controls overall MAC configuration and interfaces within management entity 170. PDU encoders (PENCO and PENCl) and decoders (PDECO and PDECl) provide channel coding/decoding for the MAC PDUs in mode 0 (incremental redundancy) or mode 1 (fixed coding). A mode 0 segment encoder

(SENCO) and decoder (SDECO) provide coding/decoding, interleaving/deinterleaving and blocking/deblocking in incremental redundancy mode of transmission.
Fig. 4 shows internal structure of a MAC transmission controller (TC) for a mobile station from Fig. 3 and located within the MAC layer 2 115, Fig. 1, of the transmitter 120. The transmission controller 192 consists of the following sub-blocks: a transmit controller (TCTX) 195, receive controller (TCRX) 200, broadcast controller (TCB) 205 and router (TCRT) 210, The transmit controller 195 is connected to the segmenter (SGMO and SGMl, Fig. 3), PDU encoder (PENCO and PENCl), CAM 180, MLC 190 and TCRT 210, Fig. 4. The TCRX 200 and TCB 205 controllers are connected to desegmenter (DSGM, Fig. 3), MLC 190 and TCRT 210, Fig. 4. The TCRT 210 is connected to TCTX 195, TCRX 200, TCB 205, MLC 190, Fig. 3, and PDU decoder (PDECO or PDECl).
Fig. 5 is a state diagram that describes a router process for &e mobile station transmission controller 192 of Fig. 4. The router 210, Fig. 4, preferably transfers decoded frames to an appropriate process (transmit, receive or broadcast controllers) within the transmission controller 192. The router 210 is also preferably employed to receive control information, such as phase assignment, poll indication, broadcast change notification and page continuation indication that may selectively be transmitted to the mobile by a peer transmission controller located at a base station. The router 210 tracks whether the mobile station is in the sleep state 215, Fig. 5, or awake state 220 and whether the AMI has been assigned to the mobile. It is appreciated that depending on tiie conditions, the router 210, Fig. 4, routes received frames accordingly.
The router 210 receives decoded frames from the CAM 180, Fig. 3, via a data.ind() primitive. The router 210, Fig. 4, may be moved by the MLC 190, Fig. 3, from tie sleep 215, Fig. 5, to awake 220 states and back via wake.req() and sleep.req() primitives respectively. The router 210, Fig. 4, issues data.ind() primitives to receive, transmit or broadcast controllers (TCRX 200, TCTX 195 and TCB 205) of Fig. 4. The router 210 informs the MLC 190, Fig. 3, about a page or pie continuation reception (via wake.ind()), broadcast change notification reception (via bcn.ind()) and new phase assignment (via phase. ind()/phase. reqO).

Fig. 6 illustrates the idle state interaction of the transmit controller 192, Fig. 4, with the CAM 180, Fig. 3, and a PDU encoder (PENCO or PENCl). Fig. 6 also illustrates an example of a fansition to the wait for assignment state.
In Fig. 6 a retrieve block for transmission in a BEGIN PDU process is preferably executed in the beginning of the uplink transaction so as to retrieve data from tiie segmenter (SGMO or SGMl Fig. 3) and to determine whether the end of transaction process should be executed based on the transaction size.
The transmit controller 192, Fig. 4, receives poll.indQ primitives from tie CAM 180, Fig. 3, widen a transmission opportunity on the uplink occurs. The transmit controller 192, Fig. 4, responds within Ae pullers primitive indicating vaster the process may selectively send data. In the idle state, the TCTX 195, Fig. 4, sends BEGIN or ARQ STATUS PDUs. If tiie CAM 180, Fig. 3, provides a transmission opportunity to this TCTX 195, Fig. 4, the TCTX 195 responds with pollconQ primitive. The TCTX 195 constructs a PDU and passes the PDU to a PDU encoder via datary and, in case of BEGIN PDU, enters the wait for assignment state. When retrieving data for BEGIN PDU, tiie TCTX 192 counts the number of data blocks in a buffer (TXBO or TX Bl, Fig. 3) and determines if it should commit to tiie end of the transaction (NB_Tx Fig. 7 shows the wait for assignment state interaction, described in Fig. 6, of the transmit controller 192, Fig. 4, with the CAM 180, Fig. 3. and PENCl. Fig. 7 also describes both a count new data blocks process and a retrieve ARQ status bitmap process. The count new data block process is preferably executed every time the TCTX 195, Fig. 4, has to determine the amount of data in the MAC buffer. Fig. 3, that has preferably never been sent over Ae air but still may selectively be included in the current transaction. The retrieve ARQ status bitmap process involves communicating with Ae receive controller (TCRX) 200. Fig. 4, to retrieve a bitmap indicating the state of the ARQ protocol for the downlink transaction.

The transmit controller 192 receives poplin() primitives trim titer tam i8U, Mg. 3, when a transmission opportunity on the uplink occurs. The transmit controller 192, Fig. 4, responds with the poll.res() primitive indicating that the transmit controller 192 may selectively send data In the wait for assignment state, the TCTX 195 may selectively send ARQ STATUS PDUs (if polled for it by peer transmission controller 192). If CAM 180, Fig. 3, provides a transmission opportunity to this TCTX 195, Fig. 4, the CAM 180, Fig. 3, sends a poll.con() primitive. The TCTX 195, Fig. 4, retrieves ARQ status bitmap, constructs a PDU, and passes the PDU to the PDU encoder via a data.req(). When counting new data blocks, the TCTX 195, Fig, 4, first checks if it has already committed to the end of current transaction (End_Tx_Flag = True). If this is the case, the TCTX 195 counts only the blocks remaining until the end of current transaction (indicated by BST_Status) and ignores data that might have arrived to the buffer (TXBO or TXBl, Fig. 3) after transaction end had been committed to. If not, the TCTX 195, Fig. 4, counts all data in MAC buffers, TXBO or TXBl, Fig. 3, (indicated by the sum of BST_Status and TXB_Status). If the number of new blocks counted in such a way is larger than NB_Max, the transaction may selectively continue as unbounded Otherwise the end procedure is required.
Fig. 8 illustrates transitions between the idle, wait for assignment and transaction in progress in mode 0 and mode 1 states. The TCTX 195, Fig. 4, may selectively transition from the wait for assignment state to one of the transaction in progress states (depending on uplink mode (UL_Mode) negotiated with the base station) after receiving positive acknowledgment to its BEGIN PDU via a PCF (as indicated by deacon() primitive from the CAM and Error=sNull condition being True) or after receiving the downlink ARQ status PDU with AMI assignment (as indicated by data.ind(ARQ_Status_Rx) primitive from TCRT 200 and conditions of WAI and AMI=AMI_Idle being False). In the wait for assignment state timers T_WA and T_BOFF_START may selectively expire and the TCTX 195 may selectively transition back to the idle states. These timers designate the amount of time the mobile station should wait for the AMI/Mode assignment via ARQ Status PDU before the mobile station is allowed to repeat its access attempt.
In the transaction in progress (mode 0 and mode 1) states, the TCTX 195 may selectively receive acknowledgments via a PCF (dataconQ from CAM 180, Fig. 3) and via ARQ Status PDU (data.ind() from TCRT 200, Fig. 4). If the transmit table 230, Fig. 12, is

empty and there is no new data (no data backlog) to send (NB_Tx Fig. 9 describes the transaction in progress state, seen in Fig. 8, interaction of the transmit controller 192, Fig. 4, with the CAM 180, Fig. 3, and Ae PDU October (PENCO or PENCl, Fig. 3). Fig. 9 also describes the find retransmit data blocks process. This process is executed selectively every time the TCTX 195, Fig, 4, determines if there are any data blocks in the transmit table 230, Fig. 12, At have not been acknowledged by the receiver and are retransmitable (i.e. &ere is a data backlog).
The transmit controller 192 receives a polling() primitives from the CAM 180, Fig. 3, veal a transmission opportunity on the uplink occurs. The transmit controller 192 responds with the poll.res() primitive indicating whether it can or must sum data In the transaction in progress state the TCTX 195, Fig. 4, may selectively send ARQ STATUS (if polled for it by peer transmission controller) or CONTINUE PDUs. If tiie CAM 180, Fig. 3, decides to provide a transmission opportunity to this TCTX 195, Fig. 4, the CAM 180, Fig. 3, sends a pollconQ primitive. The TCTX 195, Fig. 4, constructs a PDU, and passes it to the PDU encoder via data.req().
Fig. 10 describes a retrieve retransmit data blocks process. The process is executed by the TCTX 195, Fig. 4, every time TCTX 195 constructs the CONTINUE PDU which includes data blocks that have been transmitted previously but must be retransmitted again because the receiver failed to decode tied properly (i.e. another type of data backlog). The number of such data blocks depends upon the current modulation (as examples 3 blocks for 8-level modulation and 2 blocks for 4 level) and on whether Ae previously transmitted End block has to be retransmitted to inform &e receiver about the last sequence number it should expect for transaction. If the End block has to be retransmitted (End_RTx_Flag = False), the process generates the End block and places it in the SCCxT table 235, Fig. 12. If after retrieving the retransmit data blocks there is still a space remaining in the PDU, process fills this space within eerier tiie redundant End block (if the end procedure is in progress, i.e.

filler block (if the end procedure has not yet been started, i.e. End_Tx_Flag=False).
Fig. 11 illustrates a retrieve new data blocks process. This process is executed by the TCTX 195, Fig. 4, every time tiie TCTX 195 constructs the CONTINUE PDU which includes data blocks tfiat have never been transmitted previously (another type of data backlog). The number of such data blocks depends upon the current modulation (as examples 3 blocks for 8-level modulation, 2 blocks for 4 level) and on vetches the End block has to be transmitted to inform the receiver about the last sequence number it should expect for tube transaction. If &e previously transmitted End block has to be retransmitted again (End_RTx_Flag = False) or if the number of new data blocks in MAC buffers (TXBO and TXBl, Fig. 3) is smaller than a predefined threshold (NB_Tx Fig. 12 describes a construct PDU process 225, a transmit (TxT) table 230, and a sub-channel controllers transmit (SCCxT) table 235 used by the TCTX 195,Fig. 4. The construct PDU process 225 illiterates how various control and data fields in the PDUs are filled up with values and data. The TxT table 230, Fig. 12, is used to track ARQ state of the transmit controller 192, Fig. 4, i.e. the status and order of die previously transmitted data blocks within the transmit window. The SCCxT table 235 is used to track the association between blocks and the PDUs and Ae sub-channels that the PDUs have been transmitted on. The SCCxT table 235 stores information on all MAC blocks in transit that have not yet been acknowledged via a physical control field (PCF). The SCCxT table 235 is also used to facilitate construction of PDUs. Both the TxT 230 and SCCxT 235 tables are means to determine a data backlog with ^e MAC layer.
Fig. 13 shows a PCF process At is executed as part of the mobile station transmit controller 192, Fig. 4. The PCF provides acknowledgment for all blocks transmitted in the previous uplink burst on tied sub-channel. If tiie PCF indicates that the previous uplink

transmission on the sub-channel was received, a transmit table corresponding to the blocks transmitted is updated. The ARQ state variables at the TC 192 are also updated to reflect the PCF acknowledgment. The TC 192 provides a data, con signal to the segmenter (SGMO or SGMl, Fig. 3) for each block acknowledged. If tiie data blocks transmitted in the previous uplink burst on the sub-channel are negatively acknowledged via the PCF, then the data blocks are marked as retransmitable.
Fig. 14 illustrates an ARQ status process that is executed by the mobile station transmit controller 192, Fig. 4. An ARQ Status PDU may be used to assign an AMI and mode to tihe mobile station if the AMI and/or mode proposed by the mobile station are unacceptable. Altemative ly, it may indicate that the mobile station must wait for a subsequent AMI and/or mode assignment. This process also causes an update of the ARQ state variables and transmit table (TxT 230, Fig. 12) at the TC 192. If a NND field in the ARQ Status PDU is set, then the mobile station assumes that no new Layer 3 data may be transmitted. If an End block was transmitted \\4iile nearing the end of &e transaction, then the End block is acknowledged through an EBR bit in the ARQ Status PDU. If the ARQ status PDU includes a primary bitmap indicating Ae receipt status of all blocks within the receive window, then Airs bit is used to update the receipt and retransmit ability status of blocks within the transmit table (i.e., the transmit controller understands the receive window). For each block acknowledged by the bits , the TC 192 provides a data, con signal to the segmenter.
Fig. 15 shows the mobile station receive controller process in the context of transaction initiation. Fig. 15 illustrates signals obtained by the receive controller (TCRX) 200, Fig. 4, fiow the PDU decoder, PDECO or PDECl, Fig. 3 (in state Data.ind). Also shown are signals sent by the TCRX 200, Fig. 4, process to a desegmenter, DSGMO or DSGM 1, Fig. 3 (in state Detained) and MLC 190 in state StartRx.ind.
BEGIN PDUs are selectively received vole the TCRX 200, Fig. 4, is in the idle state. On receiving a BEGIN PDU fiow the PDU decoder, PDECO or PDECl, Fig. 3, the TCRX 200, Fig. 4 determines wheeler the transaction is acknowledged and ester the transaction is bounded (i.e., limited to the transfer of Br Data blocks). For ARQ transactions, the TCRX 200 also determines the ARQ mode (mode 0 or mode 1) for the

transaction and initializes an ARQ engine (also known as a TC 192, Fig. 4) in the indicated mode. The TCRX 200, Fig. 3, provides for the initiating of a MAC transaction in response to a BEGIN frame.
Fig. 16 illustrates the mobile station receive controller process while a fixed coding mode ARQ transaction is in progress. Fig. 16 shows signals received by Ae TCRX 200, Fig. 4, from the TCTX 195 (in state Pouring), MLC 190, Fig. 3, (in state StopRx.Req) and the PDU Decoder. PDECO or PDECl, Fig. 3 (in state Data.ind). Also shown are signals in Fig. 16 sent by tied TCRX 200, Fig. 4, to the TCTX 195 (the state Dataries), desegmenter, DSGMO or DSGM 1, Fig. 3 (in state error.ind), and MLC 190, Fig. 3 (in state Error.ind).
On being polled by a TC 192, Fig. 4, for ARQ Status, the TCRX 200 generates an ARQ status PDU (which contains a bitmap indicating the receipt status of all blocks in a receive window) and provides it to Ae TC 192. The CONTINUE PDUs are selectively received while a transaction is in progress. On receiving a CONTINUE PDU fiow the PDU decoder, the TCRX 200 extracts multiple blocks tom the PDU. It is appreciated that the number of blocks extracted depends on the downlink modulation. The blocks are selectively of type end, data or filler. End and filler blocks are identified by escape sequences at the start of the block. If an end block is received, the TCRX 200 preferably sets the last valid sequence number for the transaction to the sequence number indicated by the end block. For each data block extracted, die TCRX 200 executes an update receive (Rx) state process.
Fig. 17 shows Ae update Rx state process executed by the TCRX 200, Fig. 4, widen a data block is received Fig. 17 shows signals sent by tie receive controller 200 to the desegmenter, DSGMO or DSGM 1, Fig. 3 (in state Data.ind) and MLC 190, Fig. 3 in state StopRx.ind.
The receive controller 200, Fig. 4, selectively invalidates and discards tiie data block if it lies outside the window or corresponds to a block that was previously received. If the data block remains valid, Ae TCRX 200 updates Ae receipt status of the block. The receive controller 200 also updates the two state variables, NR_Rx (sequence number up to vice all data blocks have been received in-sequence) and NL_Rx (last sequence number fiat was received). The receive controller 200 then delivers all data blocks that have been received in-

sequence to the desegmenter and deletes these entries from a receive table. The process stops when the receive table is empty and NR_Rx is equal to the last valid sequence number for the transaction.
Fig. 18 shows the mobile station receive table 240, an initialize TCRX 200 parameters process 245 and a BEGIN PDU process 250 which are executed by the receive controller (TCRX) 200, Fig. 4. The receive table 240 consists of the block sequence number, data block and receipt status for each sequence number within the receive window. The initialize TCRX 200 parameters process 245 carries out an initialization of the receive table 240 and other ARQ state variables. The BEGIN PDU process 250 illustrates the initialization of the AMI, mode and the size for the transaction. It is precoated that these parameters are extracted from corresponding fields within the BEGIN PDU.
Fig. 19 shows Ae mobile station CAM process for the CAM 180, Fig. 3. Fig. 19 shows signals received from any one of the SCCs 185 (data, con, puffin, data.in4J and tiie MLC 190 (Operated, Config.req, Close.req). Fig. 19 also shows the signals sent by the CAM 180 to the transmit controller 185 (deacon), PDU decoder, PDECO or PDECl, Fig. 3 (data-ind), and MLC 190 (Error, ind).
The CAM 180 determines the order of transmission for coded MAC PDUs from multiple transmit controllers 185 (SCCO through SCCS). The CAM 180 polls the transmission controllers 185 for MAC PDUs vend it is made aware of a transmission opportunity by one of the MAC sub-channel controllers 185. Based on the response to the CAM 180 polls, the CAM 180 polls one of the transmit controllers 185 for the data. The CAM 180 selectively sends coded MAC PDUs obtained from one of Ae PDU encoders (PENCl and PENCO) to the appropriate SCC 185 for transmission over tiie air interface 175 (also known as the radio interface).
The CAM 180 is also responsible for executing a random access protocol at tiie mobile station. This friction manages channel access in contention mode and all subsequent back-off procedures in case of the failure of initial access. After successor access, the CAM 180 polls Ae transmit controllers 185 and proceeds by sending PDUs in the assigned slots indicated by sub-channel controllers 185.

In the receive direction, the CAM 180 obtains MAC PDUs from the sub-channel controller 185 and passes them on to the PDU decoder corresponding to the indicated mode.
Fig. 20 illustrates a choose transmission controller (TCy) process 255 and a send coded MAC_PDU process 260 which are executed by the CAM 180, Fig. 3. Fig. 20 shows signals sent by the CAM 180 to the TCs (TCI and TC2, Fig. 3, and poll.ind and poll.con. Fig. 20) and SCCs 185, Fig. 3 (dataries|). Fig. 20 also shows signals received from the TCs (TCI. TC2, Fig. 3 and poll.res, Fig. 20) and the PDU encoder (PENCO and PENCl, Fig. 3 and data.req. Fig. 20).
The CAM 180, Fig. 3, polls each transmit controller in order of priority ^^en it is made aware of a transmission opportunity by any SCC 185. Each TC (TCO and TCI) responds with an indication that it selectively send data, can sad data or has nothing to send. Based on Ae response, Ae CAM 180 chooses the appropriate TC (TCO and TCI) to poll for data. Subsequratly, Ae CAM 180 obtains a coded MAC PDU from die PDU encoder (PENCO and PENCl) that tiie CAM 180 provides to the appropriate SCC 185 for transmission over the air interface 175.
Fig. 21 illustrates the mobile station sub-channel controller (SCC) process. The MAC Layer has preferably 9 sub-channel controllers 185 (SCCO Rough SCCS), Fig. 3, for a triple rate channel, 6 for a double rate channel and 3 for a frill rate channel. Each subchannel controller 185 handles a packet channel feedback (PCF) operation for die subchannel and passes coded MAC PDUs between the CAM 180 and Ae physical Layer 165.
In Fig. 21, signals are received by Ae SCC 185, Fig. 3, from Ae physical Layer 165 (PHY_DATA.IND), CAM 180 (Dataries) ANSMl 190 (Open.req, Close.req). Additionally Ae signals sent by Ae SCC 185 to Ae CAM 180 (pC ind. Data. on) and Ae physical layer 165 (PHY_DATA.REQ) are shown.
On obtaining data from Ae physical layer 165, Ae SCC 185 checks Ae AMI to determine if Ae mobile station is Ae intended recipient. If Ae data is not intended for Ae mobile station, it is discarded; aeries Ae coded MAC PDU is passed on to Ae CAM 180. The SCC 185 also obtains contention and reserved access opportunities via Ae PCF and polls Ae CAM 180 for data. Any coded MAC PDU subsequently obtained from Ae CAM 180 is

tiien passed on to the physical layer 165. After the PDU is transmitted, the SCC 185 checks ftiel corresponding PCF field on the sub-chaimel in order to determine if the PDU was received successfully. The SCC 185 assumes a different PCF structure depending on whether data was transmitted using contention or reservation. The acknowledgment status obtained via PCF is indicated to the CAM 180.
Fig. 22 illustrates a check destination and extract coded MAC_PDU process that is executed by the SCC 185, Fig. 3, process on obtaining data fiow the physical layer 165. The SCC 185 may selectively send a detained signal to the CAM 180 as part of this process. On obtaining data from tiie physical layer 165, the SCC 185 checks the AMI to determine if the mobile station is the intended recipient. If the data is not intended for the mobile station, it is discarded; otherwise the coded MAC PDU is passed on to the CAM 180.
Fig. 23 shows a signal flow diagram for downlink BEGIN PDU handshake process between a base station (cell) 265 and a mobile 270 using stop and wait. The BEGIN PDU handshake establishes a unique (assigned) local identifier referred to as the AMI. The BEGIN PDU handshake also identifies the mode of operation for the subsequent operation. There are 4 possible modes of operation; fixed coding and fixed modulation; fixed coding and dative modulation; incremental redundancy and fixed modulation; and incremental redundancy and dative modulation.
In step 275, the cell 265 sends MAC layer BEGIN PDU, to the mobile 270. VSCs specifies the mode of operation of subsequent CONTINUE PDUs and assigns an AMI for the transaction. The RLP is initialized at the cell 265 on transmission of Ae BEGIN PDU and die mobile station 270 initializes Ae peer RLP on receipt of the BEGIN PDU. This step was shown in Ae state diagrams vend tiie SCC 185, Fig. 3, receives data from the physical layer 165 and passes it on to the CAM 180 in Figs. 21 and 22. The CAM 180, Fig. 3, then receives data from Ae SCC 185 and the decoded data is provided to the router (TCRT) 210, Fig. 4 (described in Ae Fig. 19 state diagram). The TCRT 210, Fig. 4 receives the data from CAM 180, Fig. 3, extracts a poll bit (PI), sets ARQ_ Status)oiled fl = PI and passes the BEGIN PDU to the TCRX 200, Fig. 4 (described in the Fig. 15). The TCRX 200, Fig. 4, receives tiie BEGIN PDU from the TCRT 210 and initializes the AMI and downlink Mode in Figs. 15 and 18.

In step 280, Ae mobile 270 provides an ARQ Status PDU (with a null biting ) acknowledging (ACK) Ae BEGIN PDU to the cell 265. This step was shown vend the SCC 185, Fig. 3, detects a transmission opportunity by reading the PCF and indicates it to CAM 180, Fig. 3, in Fig. 21. The CAM 180, Fig. 3, polls the TC TXs 195 in Figs. 19 and 20. The TCTX 195, Fig. 4, on the same step, where Begin PDU is received, indicates to the CAM 180, Fig. 3, that it selectively send an ARQ Status PDU in Fig. 6, 7 and 9. The CAM 180, Fig. 3. polls TCTX 195, Fig. 4, for ARQ Status PDU in Fig. 19. The TCTX 195, Fig. 4, polls the TCRX 200 for an ARQ Status bitmap in Fig. 7. The TCRX 200, Fig, 4, generates ARQ status and provides it to Ae TCTX 195 in Fig. 7. The TCTX 195, Fig. 4, sends the ARQ status PDU to PDU encoder (PENCO or PENC 1, Fig. 3) in Figs. 6, 7 and 9. The PDU encoder (PENCO or PENCl, Fig. 3) encodes the PDU and sends the encoder PDU to the CAM180. The CAM 180 passes the encoder PDU on to SCC 185 in Fig. 7. TheSCC185, Fig. 3, then provides data to the physical Layer 165 in Fig. 21.
In step 285, the cell 265 sends, to the mobile 270, subsequent CONTINUE PDUs in the initialized mode. This step was shown when the SCC 185, Fig. 3, receives the data from the physical Layer 165 and passes the data on to the CAM 180 in Figs. 21 and 22. The CAM 180, Fig. 3, receives tiie data from Ae SCC 185 and the decoded data is provided to the TCRT 210 (Fig. 4) in Fig 19. The TCRT 210, Fig. 4, receives the data from the CAM 180 (Fig. 3) in Fig. 5. The TCRX 200, Fig. 4, receives the Continue PDU and updates the Rx state in Figs. 16 and 17.
Fig. 24 is a signal flow diagram of the downlink BEGIN PDU handshake between the cell 265 and the mobile 270 wrought using stop and wait. In step 290, the cell 265 sends MAC layer BEGIN PDU to tied mobile 270 which specifies the mode of operation of subsequent CONTINUE PDUs, assigns an AMI for tied transaction and assigns the mobile 160 to a particular phase. The cell 265 initializes the RLP on transmission of tiie BEGIN PDU and schedules subsequent PDUs intended for Ae mobile 270 on the assigned phase. On receipt of the BEGUN PDU, the mobile station 270 initializes the peer RLP and starts listening on the assigned phase. This step was shown what Ae SCC 185, Fig. 3, receives data from tied physical layer 165 and pass it on to the CAM 180 in Figs, 21 and 22. The CAM 180, Fig. 3, then receives data from tied SCC 185 and die decoded data is provided to TCRX 200, Fig. 200, in Fig. 19. The TCRX 200, Fig. 200 receives the data from CAM 180,

Fig. 3, extracts a poll bit (PI), sets flag = PI and passes tiie Begin PDU to the TCRX 200, Fig. 4, in Fig. 5. The TCRX 200, Fig. 4, receives the Begin PDU from the TCRT 200 and initializes the AMI and downlink mode in Figs. 15 and 18.
In step 295, tie cell 265 sends subsequent CONTINUE PDUs to the mobile 270 and polls the mobile 270 for feedback. This step was shown vend tiie SCC 185, Fig. 3, receives the data from the physical Layer 165 and passes it on to the CAM 180 in Figs. 21 and 22. The CAM 180, Fig. 3, receives the data from tie SCC 185 and the decoded data is provided to the TCRT 210 (Fig. 4) in Fig 19. The TCRT 210, Fig. 4, receives the data from the CAM 180 (Fig. 3) in Fig. 5. The TCRX 200, Fig. 4, receives the CONTINUE PDU and updates the RX state in Figs. 16 and 17.
In step 300, the mobile 270 provides bitmap feedback Rough an ARQ Status PDU to the cell 265. The ARQ Status PDU may selectively indicate that the assigned mode was unacceptable. This step was shown when the SCC 185, Fig. 3, detects transmission opportunity by reading the PCF and indicates it to CAM 180 in Fig. 21. The CAM 180, Fig. 3, polls both the TC TXs (195, Fig. 4) in Figs. 19 and 20. The TCTX 195, Fig. 4, on the same step, where BEGIN PDU is received, indicates to the CAM 180, Fig. 3, that it selectively send an ARQ Status PDU in Fig. 6, 7 and 9. The CAM 180, Fig. 3, polls TCTX 195, Fig. 4, for ARQ Status PDU in Fig. 19. The TCTX 195, Fig. 4, polls the TCRX 200 for ARQ Status bet in Fig. 7. The TCRX 200, Fig. 4, generates ARQ status and provides it to the TCTX 195 in Fig. 7. The TCTX 195, Fig. 4, sends the ARQ status PDU to the PDU encoder (PENCO or PENCl, Fig. 3) in Figs. 6, 7 and 9. The PDU encoder (PENCO or PENCl, Fig. 3) recodes Ae PDU and sends Ae encoded PDU to the CAM 180. The CAM 180 passes the encoded PDU on to SCC 185 in Fig. 7. The SCC 185, Fig. 3, Thai provides data to the physical Layer 165 in Fig. 21.
Mobile stations 270, Fig. 24, initiate idling transactions tiring the transmission of a BEGIN PDU. The BEGIN PDU is selectively transmitted after through contention access or reserved access (if tiie mobile station 270 has a valid AMI). The parameters indicated by Ae BEGIN PDU include the following: tie MSID; the suggested AMI value for the transaction; die suggested mode (Incremental Redundancy or Fixed Coding) for the

transaction; a Mobile Priority Class (MPC); a downlink incremental redundancy stability; a banditti preference (full, double or triple rate); and a modulation capability.
If the mobile station 270 does not have a valid AMI, the mobile station 270 picks a random value from the set of allowable AMI values and transmits it within the BEGIN PDU as a suggested AMI. If tiie mobile station 270 ahead has a valid AMI 4ule initiating tiie transaction, it suggests the same AMI value. If the suggested AMI and mode are acceptable to Ae base station 265, it initializes an RLP and provides an acknowledgment (ACK) through the downlink tiie PCF field. On receipt of the ACK, tie mobile station 270 initializes a peer RLP. If the suggested AMI and/or mode are unacceptable to the base station 265, it provides an expect negative acknowledgment (NAK) through the downlink the PCF field. Subsequently, it transmits an ARQ Status PDU which carries out one of the following fimctions. AMI, mode and phase assignment. In dis case, base station 265 assigns an AMI value randomly picked from the set of allowable values. It may also assign a suitable mode and phase for the transaction. In the case of a wait for assignment indication, the base station 265 indicates that the mobile station 270 must wait for an AMI and/or mode assignment. The mobile station 270 computes a timer \^^ch indicates how long it must wait after receiving a NAK for a contention access attempt before making another access attempt The timer duration is a function of the wait for assignment class (WAC) value assigned by tie base station 265, and indicated through die ARQ status PDU. The WAC may be determined by the base station 265 as a fimctions of the MPC indicated by the mobile 270 in Ae BEGIN PDU. On subsequrat receipt of an ARQ status PDU while in this state, the mobile station 270 initializes an incremmtal redundancy or fixed coding RLP depending on tiie mode indicated by the downlink ARQ Status PDU. It is precoated that tiie AMI value is assigned within the ARQ Status PDU and moves to the assigned phase.
Fig. 25 is a signal flow diagram for an uplink BEGIN PDU handshake between a cell 265 and mobile 270. In sit 305, on the downlink, the mobile 270 sees PCF indication, from the cell 265, fiat Ae corresponding uplink time slot is open for contention. In step 310, the mobile 270 sends the cell 265 a MAC layer BEGIN PDU much includes (among other fields) MSID, suggested AMI and suggested mode for subsequent CONTINUE PDUs. It is appreciated that the suggested AMI may selectively be different than ftiel last 7 bits of the MSID.

Both steps 305 and 310 are also shown when the SCC 185, Fig. 3, receives tiie contention slot indication via Ae PCF and indicates a transmission opportunity to the CAM 180 in Fig. 21. The CAM 180, Fig. 3, polls both the TCTXs (195, Fig. 4) in Figs. 19 and 20. The TCTX 195, Fig. 4, on one of the SAPs (SAPO or SAPl, Fig. 3) indicates to the CAM 180 that it can send a BEGIN PDU in Fig. 6. The CAM 180, Fig. 3, polls the TCTX 195, Fig. 4, for the BEGIN PDU in Fig. 19. The TCTX 195, Fig. 4, sends the BEGIN PDU to the PDU encoder (PENCO or PENCl, Fig. 3) in Fig. 6. The PDU encoder (PENCO or PENCl, Fig. 3) encodes Ae PDU and sends the encoded PDU to the CAM 180 which passes it on to the SCC 185 in Fig. 19. The SCC 185, Fig. 3, provides the data to the physical Layer 165 in Fig. 21.
In step 315, if Ae suggested AMI is not being used by any mobiles currently active on the channel and if Ae suggested mode is acceptable to the cell 265, the cell 265 assigns the suggested AMI to the mobile 270 and acknowledges the BEGIN PDU through tie PCF mechanism The PCF ACK indicates that the suggested AMI and mode are both acceptable to the cell 265, and the mobile 270 may start transmitting subsequent CONTINUE PDUs. Step 315 was also shown whine the SCC 185, Fig. 4, receives an ACK to the transmission of the BEGIN PDU via the PCF and indicates it to the CAM 180 (Fig. 3) in Fig. 21. The CAM 180, Fig. 3, provides a confirmation to the TCTX 195, Fig. 4, that the BEGIN PDU was received in Fig. 19. The TCTX 195, Fig. 4, initializes a radio link protocol (RLP) for the mode described earner in Figs. 8 and 10.
In step 320, tied cell 265 indicates to the mobile 270, through the PCF, that the mobile 270 may selectively proceed with transmission in the next slot In step 325, die mobile 270 sends subsequent CONTINUE PDUs in the initialized mode to the cell 265. It is appreciated to one skilled in Ae art At steps 320 and 325 may selectively be combined in one transmission or selectively sent in different time slots.
Boa steps 320 and 325 where shown earlier vend the SCC 185, Fig. 3, receives a reservation slot indication via the PCF and indicates a transmission opportunity to CAM 180 inFig.21. The CAM 180. Fig. 3, polls both the TCTXs (195, Fig. 4) in Figs. 19and20. The TCTX 195, Fig. 4 ,on one of the active SAP (SAPO or SAPl, Fig. 3) indicates to the CAM 180 that it can send a CONTINUE PDU in Fig. 9. The CAM 180, Fig. 3, polls the

TCTX 195, Fig. 4, for the CONTINUE PDU in Fig. 19. The TCTX 195, Fig. 4, sends CONTINUE PDU to the PDU encoder (PENCO or PENCl, Fig. 3) in Fig. 9. The PDU encoder (PENCO or PENCl, Fig. 3) encodes the PDU and sends the encoded PDU to the CAM 180 which passes it on to the SCC 185 in Fig. 19. The SCC 185, Fig. 3, provides the data to the physical Layer 165 in Fig. 21.
The event tiiat multiple mobiles transmit in the same contention slot and suggest the same AMI is considered unlikely. However, in the unlikely case that this event occurs, thieve mobiles assume the same AMI. It is possible to resolve the ambiguity by optionally transmitting the MSID and AMI as a part of the ARQ Status PDUs on the downlink.
Fig. 26 shows a signal flow diagram for an pump BEGIN PDU handshake between the cell 265 and the mobile 270. In step 330, on the downlink, the mobile 270 sees the PCF indication fiat tie corresponding uplink time slot is open for contention at cell 265. In step 335, the mobile 270 sends BEGIN PDU to the cell 265 vice includes (among oater fields) MSID, suggested AMI and suggested mode.
Both steps 330 and 335 are also show vend the SCC 185, Fig. 3, receives 4e contention slot indication via the PCF and indicates a transmission opportunity to the CAM 180 in Fig. 21. The CAM 180 polls both the TCTXs (195, Fig. 4) in Figs. 19 and 20. The TCTX 195, Fig. 3, on one of the SAPs (SAPO or SAPl) indicates to the CAM 180 that it can send a BEGIN PDU in Fig. 6. Hei CAM 180, Fig. 3, polls the TCTX 195, Fig. 4, for the BEGIN PDU in Fig. 19. Hei TCTX 195, Fig. 4, sends the BEGIN PDU to the PDU encoder (PENCO or PENCl, Fig. 3) in Fig. 6. The PDU encoder (PENCO or PENCl, Fig. 3) encodes the PDU and sends tie encoded PDU to the CAM 180 which passes it on to the SCC 185 in Fig. 19. The SCC 185 provides the data to the physical Layer 165 in Fig. 21.
In step 340, if die suggested AMI is already being used by an active mobile 270 or if tiie suggested mode is unacceptable, the cell 265 does not acknowledge &e reception of the PDU to the mobile 270. Step 340 corresponds to the SCC 185, Fig. 3, receiving a negative acknowledger to the transmission of tiie BEGIN PDU via the PCF and indicates it to the CAM 180 in Fig. 21. The CAM 180, Fig. 3, indicates to the TCTX 195, Fig. 4, that the BEGIN PDU was not received in Fig. 19.

In step 345, the cell 265 sends an ARQ Status PDU to the mobile 270 \\toch acknowledges reception of BEGIN PDU and assigns the AMI and/or establishes the mode to be used for subsequent . The SCC 185, Fig. 3, receives the data from the physical Layer 165 and passes it on to the CAM 180 in Figs. 21 and 22. The CAM 180, Fig. 3, receives the data from tie SCC 185 and the decoded data is provided to the router (TCRT 210, Fig. 4) in Fig. 19. The TCRT 210, Fig. 4, receives the data from the CAM 180, Fig. 3, and passes the ARQ Status PDU to the TCTX 195 (Fig. 4) in Fig. 5. The TCTX 195, Fig. 4, receives the ARQ Status PDU from the TCRT 210 and initializes AMI and RLP in the uplink. The mode is indicated in Figs. 8 and 11.
In step 350, tiie cell 265 indicates to the mobile 270, furloughs Ae PCF, data mobile 270 may proceed with transmission in the next slot. In step 355, the mobile 270 confirms the new AMI in its first CONTDSTUE PDU, In step 360, the mobile 270 sends subsequent CONTINUE PDUs to the cell 265. It is appreciate by one skilled in the art that step 350, 355 and 360 may selectively be combined in one transmission or sent in differ slots.
In steps 350,355 and 360, the SCC 185, Fig. 3, receives a reservation slot indication via the PCF and indicates a transmission opportunity to CAM 180 in Fig. 21. The CAM 180, Fig. 3, polls boA the TCTXs (195, Fig. 4) in Figs. 19 and 20. The TCTX 195, Fig. 4, on one of the active SAP (SAPO or SAPl, Fig. 3) indicates to the CAM 180 that it can send a CONTINUE PDU in Fig. 9. The CAM 180, Fig. 3, polls the TCTX 195, Fig. 4, for the CONTINUE PDU in Fig. 19. The TCTX 195, Fig. 4, sends CONTINUE PDU to the PDU encoder (PENCO or PENCl, Fig. 3) in Fig. 9. The PDU encoder (PENCO or PENCl, Fig. 3) encodes the PDU and sends to the CAM 180 which passes it on to the SCC 185 in Fig. 19. The SCC 185, Fig. 3, provides the data to the physical Layer 165 in Fig. 21.
In the case A\4iere an transaction is initiated using a BEGIN PDU, and a simultaneous downlink transaction is initiated before the completion of the BEGIN PDU handshake. The uplink BEGIN PDU suggests an AMI and a mode for the transaction. A downlink transaction may be initiated before tiie cell acknowledges reception of the BEGIN PDU through PCF. In such cases, the BEGIN PDU on the downlink assigns an AMI ^^4lich may or may not be same as the AMI suggested by Ae mobile. In order to avoid any

potential ambiguity, the AMI assigned using the downlink BEGIN PDU is assumed to take precedence.
Fig. 27 illustrates a signal flow diagram for an AMI assigned on the downlink different from AMI suggested on the uplink. In step 365, on the downlink, mobile 270 sees the PCF indication that tied corresponding uplink time slot is open for contention with Ae cell 265. In step 370, the mobile 270 sends BEGIN PDU which includes (among oar fields) MSID, suggested AMI and suggested mode. In step 375, the cell 265 sends BEGIN PDU which specifies the mode of operation on the downlink and also assigns an AMI. This AMI value is different fiow the AMI suggested by the mobile station 270. In step 380, the cell 265 does not acknowledge the reception of the uplink BEGIN PDU. In step 385, tied cell 265 sends an ARQ Status PDU to the mobile 270 which acknowledges reception of BEGIN PDU and assigns die AMI and/or establishes the mode to be used for subsequent CONTINUE PDUs. In step 390, the cell 265 indicates to the mobile 270, through the PCF, that it may proceed with transmission in the next slot. In step 395, the mobile 270 confirms a new AMI in its first CONTINUE PDU. In step 400, the mobile 270 sends subsequent CONTINUE PDUs to the cell 265. It is appreciated by one skilled in the art that steps 390, 395 and 400 may selectively combined in one transmission or sent in different time slots.
Fig. 28 is a flow diagram illustrating an AMI assigned on downlink that is the same as AMI suggested on tiie uplink. In step 405, on the downlink, mobile 270 sees the PCF indication that the corresponding uplink time slot is open for contention. In step 410, the mobile 270 sends BEGIN PDU to the cell 265 which includes (among other fields) MSID, suggested AI^ and suggested mode for subsequent CONTINUE PDUs. In step 415, the cell 265 transmits BEGIN PDU vetch establishes the mode of operation on tfie downlink and assigns an AMI. The assigned AMI shapes to be the same as the one suggested by tiie mobile 270. In step 420, if the suggested mode is acceptable to tied cell 265, the cell 265 acknowledges the BEGIN PDU Rough the packet channel feedback (PCF) mechanism. The PCF ACK indicates that tiie suggested AMI and mode are both acceptable to tiie cell 265, and the mobile 270 may start transmitting subsequent CONTINUE PDUs. In step 425, the cell 265 indicates to tfie mobile 270, tiring PCF, that it may proceed with transmission in the next slot In step 430, the mobile 270 sends subsequent CONTINUE PDUs in the

initialized mode. It is precoated by one skilled in the art that steps 425 and 430 may selectively combined in one transmission or sent in different time slots.
Stated generally, the present invention is a method of implementing a radio link protocol (RLP) and dynamic partial echo management for a transaction oriented packet data communication system. The method performs the steps of determining a data backlog (in the buffers TXBO and TXBl, Fig. 3) with a media access control layer controller (MLC 190), and transmitting a BEGIN PDU to a receiver 167. The method further includes the step of initiating a media access control layer transaction (at the MLC 190) in response to the transmitting of the BEGIN PDU. The data backlog is indicated to tiie media access controller by a network layer 160. The mention further includes the steps of stopping data transmission after transmitting the BEGIN protocol data unit, and waiting for an acknowledgment message from the receiver 167. The acknowledgment message from the receiver 167 is controlled by the sub-channel controllers 185,
The present invention is also a system for implementing a radio link protocol (RLP) and dynamic partial echo management for a transaction oriented packet data system. The system comprises a media access control layer controller 190 for determining a data backlog in a media access control layer buffer (TXBO and TXBl) and a media access control layer transmitter 166 for transmitting a BEGIN PDU to a receiver 167. The system also includes a means for initiating (such as MCL 190 or management entity 170) a media access control layer transaction in response to the transmitting of the BEGIN PDU.
While the specification in this invention is described in relation to certain implementations or embodiments, many details are set forth for the purpose of illustration. Thus, the foregoing merely illustrates the principles of the invention. For example, this invention may have other specific forms without departing from its spirit or essential characteristics. The described arrangements are illustrative and not restrictive. To those skilled in tiie art, the invention is susceptible to additional implementations or embodiments and certain of tiie details described in this application can be varied considerably without departing from tiie basic principles of the invention. It will tidies be appreciated tiiat those skilled in tiie art will be able to devise various arrangements which, slough not explicitly

described or shown herein, embody the principles of the invention are thus within its spirit and scope.




WE CLAIM :
1. A method of implementing a radio link protocol for a transaction oriented
packet data communication system comprising the steps of:
determining a data.backlog with a media access control layer controller;
transmitting to a receiver, a BEGIN protocol data unit, characterised in that
assigning a proposed temporary identity to be used for the duration of a transaction; and
initiating a media access control layer transaction in response to acceptance, by the receiver, of the proposed temporary identity as a unique temporary identity in the communication system.
2. The method as claimed in claim 1, wherein the BEGIN protocol data unit is transmitted by a mobile station to the communication system.
3. The method as claimed in claim 2, wherein the initiating step comprises the step of acknowledging by control of a sub-channel controller, the BEGIN protocol data unit at the media access control layer controller signifying the acceptance of the proposed temporary identity in the media access control layer transaction.
4. The method as claimed in claim 1, wherein the data backlog is indicated to the media access controller by a network layer.
5. The method as claimed in claim 1, comprising the step of stopping data transmission after transmitting the BEGIN protocol data unit, and the step of waiting for an acknowledgement message from the receiver.

The method as claimed in claim 5, wherein the steps are performed at a transmission controller.
The method as claimed in claim 1, comprising the step of transmitting at least one CONTINUE protocol data unit after initiating the media access control layer transaction with the media access control layer controller.
The method as claimed in claim 1, comprising the step of establishing an assigned local identifier used by the transmitter and the receiver for the duration of the transaction.
The method as claimed in claim 1, comprising the step of identifying a mode of operation for subsequent implementations of radio link protocols and dynamic temporary identity management for the transaction oriented packet data system.
The method as claimed in claim 9, wherein the mode of operation is either fixed coding and fixed modulation, or is fixed coding and adaptive modulation, or is incremental redundancy coding and fixed modulations, or is incremental redundancy coding and adaptive modulation.
The method as claimed in claim 1, wherein the transmitter initializes a radio link protocol upon transmission of the BEGIN protocol data unit, and / or the receiver further initializes a radio link protocol upon receiving the BEGIN protocol data unit.
The method as claimed in claim 1, wherein the receiver provides the proposed identity as an acknowledgement to the transmitter in response to the BEGIN protocol data unit when the proposed identity is a unique temporary identity in the communication system.

The method as claimed in claim 1, wherein the unique temporary lenity is utilized for transactions in both directions.
A communication system for carrying out the method claimed in any one of the preceding claims.


Documents:

550-mas-1999-abstract.pdf

550-mas-1999-assignement.pdf

550-mas-1999-claims filed.pdf

550-mas-1999-claims granted.pdf

550-mas-1999-correspondnece-others.pdf

550-mas-1999-correspondnece-po.pdf

550-mas-1999-description(complete)filed.pdf

550-mas-1999-description(complete)granted.pdf

550-mas-1999-drawings.pdf

550-mas-1999-form 1.pdf

550-mas-1999-form 26.pdf

550-mas-1999-form 3.pdf

550-mas-1999-form 4.pdf

abs-550-mas-1999.jpg


Patent Number 210247
Indian Patent Application Number 550/MAS/1999
PG Journal Number 50/2007
Publication Date 14-Dec-2007
Grant Date 25-Sep-2007
Date of Filing 12-May-1999
Name of Patentee M/S. LUCENT TECHNOLOGIES INC
Applicant Address 600 MOUNTAIN AVENUE, MURRAY HILL, NEW JERSEY 07974-0636,
Inventors:
# Inventor's Name Inventor's Address
1 KRISHNA BALACHANDRAN 1506 KNOLLWOOD DRIVE, MIDDLETOWN, NEW JERSEY 07748,
2 RICHARD PAUL EJZAK , 710 ARBOR AVENUE, WHEATON, ILLINOIS 60187,
3 SHIV MOHAN SETH 1167 BLACK STALLION DRIVE, NAPERVILLE, ILLINOIS 60540,
PCT International Classification Number H 04 B 7/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/085,752 1998-05-17 U.S.A.