Title of Invention	METHOD FOR SAVING POWER IN A WIRELESS DEVICE DURING NO ACKNOWLEDGEMENT SESSION
Abstract	The invention proposes a method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame. It determines whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number and accordingly switches the wireless device to power saving mode for tghe period transmissions are found void. The system according to the invention features a sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and a target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission.

Title of Invention

METHOD FOR SAVING POWER IN A WIRELESS DEVICE DURING NO ACKNOWLEDGEMENT SESSION

Abstract

The invention proposes a method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame. It determines whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number and accordingly switches the wireless device to power saving mode for tghe period transmissions are found void. The system according to the invention features a sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and a target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission.

Full Text	FIELD OF THE INVENTION The present invention relates to the field of communication systems and specifically relates to power saving in wireless devices. More particularly, the present invention relates to system and method for active power saving during No-Ack sessions. DESCRIPTION OF THE RELATED ART Power saving methods is very crucial for efficient and prolonged usage of wireless devices in communication systems. There are enough literature in respect of power saving methods employed in prior art. For Example a patent Publication titled 'Power saving method for a wireless network communication device' (US 20060045035A1) describes a method to save power for a wireless communication network device. According to the method, the target device parses the header of the received data unit in order to determine whether the packet is useful for the receiver or not. In the event of the data unit being found useless, the receiver automatically goes to a power saving state. The duration for which the receiver remains in the power saving state is the total transmission time of the remaining frames of the data unit. Another patent Publication titled 'Radio communication system' (US20060072614A1) describes a wireless communication system which provides for a sleep mode for the receiver in case the data transmitted by the source is not addressed to the said receiver. According to the publication, the source indicates the duration of the transmitted frame in the header of the transmitted packet. The receiver parses the PLCP header and calculates the time required to transmit the entire frame (including Inter Frame Space), in case the destination for the packet is not the said receiver, the receiver goes into sleep mode in order to save power. However none of the above referred patent documents mention the concept of power saving during No-Ack sessions in a wireless system. Hence, based upon the foregoing, there has been felt the need for a method, which effectively addresses effective power saving during No-Ack sessions. The present invention proposes a method for active power saving in a wireless device serving as the target device in a No Acknowledgement session in a wireless system SUMMARY OF THE INVENTION It is therefore the primary object of the present invention to provide a method to save power in a wireless system during a No-Ack session by invoking active power mode. It is yet another object of the invention to provide a system comprising, a sender device which performs continues transmission in a No-Ack session and a target device which enters power saving mode for the period transmissions are found void. Accordingly the present invention provides a method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame, the method comprising, • Parsing the header containing duration field wherein each fragment is set on the sender side as the sum of the transmission time of the current fragment and the remaining fragments, to determine whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number. • Extracting the duration of the currently received fragment incase a missed fragment is detected. • Switching the wireless device to power saving mode for the extracted duration. Also, the present invention provides a system for efficient power saving during a No Acknowledgement session, the system comprising, • A sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and • A target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission. These and other objects, features, and advantages of the present invention will become more apparent from the ensuing detailed description of the invention. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS Figure 1 depicts the method for active mode power saving. DETAILED DESCRIPTION OF INVENTION The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore the details disclosed herein are not to be interpreted as limiting but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make or use the invention. The present invention utilizes a WiMedia Target device capability to determine missed fragments in an MSDU. This invention utilizes the duration field of the WiMedia MAC Header to determine the remaining time required for transmitting remaining fragments of an MSDU. Based on this field, a WiMedia target device chooses to put the radio power in IDLE mode for that duration, in case of missed fragments during No-ACK Sessions. According to the present invention, the target WiMedia MAC device determines a missed fragment of an MSDU based on the expected and received Sequence Number. 1. Sequence Number is a combination of MSDU Id and Fragment Number(MSDUJD, FRAG_NUM) 2. A target MAC device upon receiving a (MSDUJD, FRAGJMUM) will update the expected Sequence Number to (MSDUJD, FRAG_NUM + 1) if more fragments for the same MSDUJD is expected. 3. If the reoeived fragment is the last fragment of that MSDUJD, the target MAC device updates the expected Sequence Number to the (MSDUJD + 1,0). If the target MAC device receives a fragment which has the Sequence Number greater than the expected Sequence Number but belonging to the same MSDUJD, the target MAC device will discard the received and remaining fragments of the MSDUJD when using the No-ACK as ARQ policy. In the sender side, the duration field in each of the fragment is set to the sum of transmission time of the current fragment plus the transmission times of the remaining fragments till the last fragment of an MSDU, including IFSs. This has to be implemented in sender side MAC device in order to achieve the active mode power save in the receiver side. We propose, in the target side, to determine any missed fragment, upon which to initiate the active mode power saving. The target parses the PLCP header of each received frame and determines if it has received a frame correctly or if it has missed any fragments. If the target device determines a missed fragment, it extracts the duration field from the currently received fragment and puts the radio mode to IDLE state from the (current time) till (current time plus duration value). According to a preferred embodiment of the invention, the wireless device enters power saving mode by putting the radio to IDLE state whenever a fragment is missed during a No-ACK Session till the next MSDUJD is expected to be received. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart there from. GLOSSARY OF TERMS AND DEFINITIONS THEREOF No-ACK: No Acknowledgement. A sender does not wait for acknowledgement to the currently transmitted MAC frame. Regardless of whether the target device received frames or not, the sender continues transmission. MSDUJD: MAC Service Data Unit. The unit of payload submitted by a MAC Client. FRAG_NUM: The MSDU submitted by a MAC Client will be fragmented by the WiMedia MAC. It can fragment upto a maximum of 8 fragments. Radio Power: The PHY RF antenna power is considered to be radio power. A device consumes maximum power when in RX mode, minimum power when in IDLE mode and zero power when in SLEEP or OFF mode. WE claim 1. A method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame, the method comprising, a) Parsing the header containing duration field wherein each fragment is set on the sender side as the sum of the transmission time of the current fragment and the remaining fragments, to determine whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number. b) Extracting the duration of the currently received fragment incase a missed fragment is detected. c) Switching the wireless device to power saving mode for the extracted duration. 2. The method according to claim 1, wherein the wireless device enters active mode by putting the radio power into IDLE state in order to save power. 3. The method according to claim 1, wherein the wireless device is a WiMedia target device. 4. The method according to claim 1, wherein the wireless device increments the fragment number field of sequence number by one. 5. The method according to claim 1, wherein the wireless device increments the MSDU ID by one and sets the fragment number as zero when the current fragment is the last fragment 6. The method according to claim 1, wherein the wireless device on receipt of a fragment with sequence number greater than the expected sequence number but belonging to the same MSDUJD discards the received fragment and the remaining fragments having the MSDUJD. 7. A system for efficient power saving during a No Acknowledgement session, the system comprising, a sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and a target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission. 8. A method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame substantially as herein described with reference to the accompanying drawing. 9. A system for efficient power saving during a No Acknowledgement session substantially as herein described with reference to the accompanying drawing Dated this the 21st day of December 2007 IANTOSH VIKRAM SINGH Patent Agent Agent for the Applicant

Full Text

FIELD OF THE INVENTION
The present invention relates to the field of communication systems and specifically relates to power saving in wireless devices. More particularly, the present invention relates to system and method for active power saving during No-Ack sessions.
DESCRIPTION OF THE RELATED ART
Power saving methods is very crucial for efficient and prolonged usage of wireless devices in communication systems.
There are enough literature in respect of power saving methods employed in prior art. For Example a patent Publication titled 'Power saving method for a wireless network communication device' (US 20060045035A1) describes a method to save power for a wireless communication network device. According to the method, the target device parses the header of the received data unit in order to determine whether the packet is useful for the receiver or not. In the event of the data unit being found useless, the receiver automatically goes to a power saving state. The duration for which the receiver remains in the power saving state is the total transmission time of the remaining frames of the data unit.
Another patent Publication titled 'Radio communication system' (US20060072614A1) describes a wireless communication system which provides for a sleep mode for the receiver in case the data transmitted by the source is not addressed to the said receiver. According to the publication, the source indicates the duration of the transmitted frame in the header of the transmitted packet. The receiver parses the PLCP header and calculates the time required to transmit the entire frame (including Inter Frame Space), in case the destination for the packet is not the said receiver, the receiver goes into sleep mode in order to save power.
However none of the above referred patent documents mention the concept of power saving during No-Ack sessions in a wireless system.
Hence, based upon the foregoing, there has been felt the need for a method, which effectively addresses effective power saving during No-Ack sessions. The present invention proposes a method for active power saving in a wireless device serving as the target device in a No Acknowledgement session in a wireless system
SUMMARY OF THE INVENTION
It is therefore the primary object of the present invention to provide a method to save power in a wireless system during a No-Ack session by invoking active power mode.
It is yet another object of the invention to provide a system comprising, a sender device which performs continues transmission in a No-Ack session and a target device which enters power saving mode for the period transmissions are found void.
Accordingly the present invention provides a method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame, the method comprising,
• Parsing the header containing duration field wherein each fragment is set on the sender side as the sum of the transmission time of the current fragment and the remaining fragments, to determine whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based
on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number.
• Extracting the duration of the currently received fragment incase a missed fragment is detected.
• Switching the wireless device to power saving mode for the extracted duration.
Also, the present invention provides a system for efficient power saving during a No Acknowledgement session, the system comprising,
• A sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and
• A target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission.
These and other objects, features, and advantages of the present invention will become more apparent from the ensuing detailed description of the invention.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS Figure 1 depicts the method for active mode power saving.
DETAILED DESCRIPTION OF INVENTION
The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore the details disclosed herein are not to be interpreted as limiting but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make or use the invention.
The present invention utilizes a WiMedia Target device capability to determine missed fragments in an MSDU. This invention utilizes the duration field of the WiMedia MAC Header to determine the remaining time required for transmitting remaining fragments of an MSDU. Based on this field, a WiMedia target device chooses to put the radio power in IDLE mode for that duration, in case of missed fragments during No-ACK Sessions.
According to the present invention, the target WiMedia MAC device determines a missed fragment of an MSDU based on the expected and received Sequence Number.
1. Sequence Number is a combination of MSDU Id and Fragment Number(MSDUJD, FRAG_NUM)
2. A target MAC device upon receiving a (MSDUJD, FRAGJMUM) will update the expected Sequence Number to (MSDUJD, FRAG_NUM + 1) if more fragments for the same MSDUJD is expected.
3. If the reoeived fragment is the last fragment of that MSDUJD, the target MAC device updates the expected Sequence Number to the (MSDUJD + 1,0).
If the target MAC device receives a fragment which has the Sequence Number greater than the expected Sequence Number but belonging to the same MSDUJD, the target MAC device will discard the received and remaining fragments of the MSDUJD when using the No-ACK as ARQ policy.
In the sender side, the duration field in each of the fragment is set to the sum of transmission time of the current fragment plus the transmission times of the remaining fragments till the last fragment of an MSDU, including IFSs. This has to be implemented in sender side MAC device in order to achieve the active mode power save in the receiver side.
We propose, in the target side, to determine any missed fragment, upon which to initiate the active mode power saving. The target parses the PLCP header of each received frame and determines if it has received a frame correctly or if it has missed any fragments. If the target device determines a missed fragment, it extracts the duration field from the currently received fragment and puts the radio mode to IDLE state from the (current time) till (current time plus duration value).
According to a preferred embodiment of the invention, the wireless device enters power saving mode by putting the radio to IDLE state whenever a fragment is missed during a No-ACK Session till the next MSDUJD is expected to be received.
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are possible and are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart there from.
GLOSSARY OF TERMS AND DEFINITIONS THEREOF
No-ACK: No Acknowledgement. A sender does not wait for acknowledgement to the currently transmitted MAC frame. Regardless of whether the target device received frames or not, the sender continues transmission.
MSDUJD: MAC Service Data Unit. The unit of payload submitted by a MAC Client.
FRAG_NUM: The MSDU submitted by a MAC Client will be fragmented by the WiMedia MAC. It can fragment upto a maximum of 8 fragments.
Radio Power: The PHY RF antenna power is considered to be radio power. A device consumes maximum power when in RX mode, minimum power when in IDLE mode and zero power when in SLEEP or OFF mode.

WE claim
1. A method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently transmitted MAC frame, the method comprising,
a) Parsing the header containing duration field wherein each fragment is set on the sender side as the sum of the transmission time of the current fragment and the remaining fragments, to determine whether a fragment has been missed in a transmitted MAC Service Data Unit (MSDU) based on the expected sequence number and received sequence number both bearing respective MSDU ID and fragment number.
b) Extracting the duration of the currently received fragment incase a missed fragment is detected.
c) Switching the wireless device to power saving mode for the extracted duration.
2. The method according to claim 1, wherein the wireless device enters active mode by putting the radio power into IDLE state in order to save power.
3. The method according to claim 1, wherein the wireless device is a WiMedia target device.
4. The method according to claim 1, wherein the wireless device increments the fragment number field of sequence number by one.
5. The method according to claim 1, wherein the wireless device increments the MSDU ID by one and sets the fragment number as zero when the current fragment is the last fragment
6. The method according to claim 1, wherein the wireless device on receipt of a fragment with sequence number greater than the expected sequence number but belonging to the same MSDUJD discards the received fragment and the remaining fragments having the MSDUJD.
7. A system for efficient power saving during a No Acknowledgement session, the system comprising, a sender device which continues transmission irrespective of whether the target device confirms the receipt of the transmitted frame or not, and a target device which switches power saving mode for a computed duration on determination that a fragment has been missed in transmission.
8. A method for saving power in a wireless device serving as the target device in a No Acknowledgement session in a wireless system in which the sender is not obliged to wait for acknowledgement to the currently
transmitted MAC frame substantially as herein described with reference to the accompanying drawing.
9. A system for efficient power saving during a No Acknowledgement session substantially as herein described with reference to the accompanying drawing
Dated this the 21st day of December 2007
IANTOSH VIKRAM SINGH
Patent Agent Agent for the Applicant

Documents:

2412-CHE-2006 AMENDED PAGES OF SPECIFICATION 27-03-2013.pdf

2412-CHE-2006 AMENDED CLAIMS 27-03-2013.pdf

2412-CHE-2006 EXAMINATION REPORT REPLY RECEIVED 27-03-2013.pdf

2412-CHE-2006 FORM-1 27-03-2013.pdf

2412-CHE-2006 FORM-13 27-03-2013.pdf

2412-CHE-2006 FORM-3 27-03-2013.pdf

2412-CHE-2006 OTHER PATENT DOCUMENT 27-03-2013.pdf

2412-CHE-2006 POWER OF ATTORNEY 06-08-2013.pdf

2412-CHE-2006 POWER OF ATTORNEY 27-03-2013.pdf

2412-CHE-2006 ABSTRACT.pdf

2412-CHE-2006 AMENDED CLAIMS 13-06-2013.pdf

2412-CHE-2006 AMENDED PAGES OF SPECIFICATION 13-06-2013.pdf

2412-CHE-2006 CLAIMS.pdf

2412-CHE-2006 CORRESPONDENCE OTHERS 06-08-2013.pdf

2412-CHE-2006 CORRESPONDENCE OTHERS.pdf

2412-CHE-2006 DESCRIPTION (COMPLETE).pdf

2412-CHE-2006 DRAWINGS.pdf

2412-CHE-2006 EXAMINATION REPORT REPLY RECEIVED 13-06-2013.pdf

2412-CHE-2006 FORM-1.pdf

2412-CHE-2006 FORM-18.pdf

2412-CHE-2006 FORM-3 13-06-2013.pdf

2412-CHE-2006 OTHERS 13-06-2013.pdf

2412-CHE-2006 POWER OF ATTORNEY 13-06-2013.pdf

2412-che-2006-correspondnece-others.pdf

2412-che-2006-description(provisional).pdf

2412-che-2006-drawings.pdf

2412-che-2006-form 1.pdf

2412-che-2006-form 26.pdf

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Patent Number

256993

Indian Patent Application Number

2412/CHE/2006

PG Journal Number

35/2013

Publication Date

30-Aug-2013

Grant Date

23-Aug-2013

Date of Filing

22-Dec-2006

Name of Patentee

SAMSUNG INDIA SOFTWARE OPERATIONS PRIVATE LIMITED

Applicant Address

BAGMANE LAKEVIEW, BLOCK 'B', NO. 66/1, BAGMANE TECH PARK, C V RAMAN NAGAR, BYRASANDRA, BANGALORE - 560 093.

Inventors:

#	Inventor's Name	Inventor's Address
1	SWAMINATHAN SUNDARESAN	BAGMANE LAKEVIEW, BLOCK 'B', NO. 66/1, BAGMANE TECH PARK, C V RAMAN NAGAR, BYRASANDRA, BANGALORE - 560 093.

PCT International Classification Number

G06F3/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA