Title of Invention

METHOD FOR WAKE PERIOD ANNOUNCEMENT IN WIRELESS NETWORKS

Abstract

This invention relates to the field of wireless networks and to medium access control for wireless personal area networks that are based on wireless mobile ad-hoc networks. This invention relates to devices that send their beacons to announce their existence and to power save and wakeup mechanisms of devices in wireless networks. Also the invention provides mechanisms for announcement of local wakeup intervals and global wakeup intervals of the device operating in wireless network.

Full Text

FIELD OF TECHNOLOGY This invention relates to the field of wireless networks and to medium access control for wireless personal area networks that are based on wireless mobile ad-hoc networks. Further, this invention relates to devices that send their beacons to announce their existence and to power save and wakeup mechanisms of devices in wireless networks. The invention provides mechanisms for announcement of local wakeup intervals and global wakeup intervals of the device operating in wireless network. More particularly, this invention encompasses a system and method for announcement of local and global wakeup intervals in wireless personal area networks based on ultra wide band (UWB) systems. DESCRIPTION OF RELATED ART The wireless personal area networks are defined to operate in the personal operating space, i.e. in a range of approximately 10 meters. The IEEE (http://www.ieee.org) is involved in defining standards for such wireless personal area networks. The Ultra Wide Band (UWB) technology can provide data rates exceeding several hundreds of Mbps in this personal operating space. In wireless personal area networks, the medium is shared between all the devices for communication with each other. This necessitates a medium access control mechanism for the devices to manage medium access, broadly including how they may join the network, how they can transfer data at the required rate to another device, how the medium is best used, how to detect and resolve beacon collisions, etc. Medium access control for wireless personal area networks can be designed in two approaches - centralized and distributed. In the centralized approach, one of the device acts on behalf of the whole network to coordinate in managing the medium access operations for all the devices. All other devices seek help of the centralized coordinator for medium access operations like joining the network, reserving channel time, etc. In the Distributed approach, the medium access operations are distributed evenly across all devices in the network and all the devices share the load of managing medium access operations for each other. While the IEEE standards employ a centralized medium access control mechanisms, some distributed medium access control mechanisms are under discussions for WPANs as they offer flexibility in terms of mobility of devices. Figure 1 illustrates a wireless personal area network, which is based on distributed approach and which does not have any centralized coordinator. It involves a decentralized WPAN, in which devices are light coordinator and there is no dedicated coordinator present. All devices cooperate and share information with each other to perform the medium access control tasks such as allowing a new device to join, allocation of channel time to a device to transmit data to another device, synchronization mechanisms, etc. This is a Distributed WPAN system which is formed in an ad-hoc fashion. Each device periodically broadcasts the information about its neighbors and allocated channel time to its neighbors. The Distributed medium access control approach relies on a timing concept called the Superframe. Superframe has a fixed length in time and is divided into a number of time windows which are called time slots. Some of the time slots are used by the devices to send their beacons and the other are used by the devices to send the data. The slots in which beacons are sent are called beacon slots and the slots in which data is sent are called data slots. The length of a beacon period may be less than the length of a data period. The beacon slots may be distributed across the slots in the superframe or may appear together at the start of the superframe. In addition, the number of beacon slots may be fixed or variable leading to different configurations of Distributed Medium Access Control mechanisms. Figure 2 illustrates the superframe structure, specified by the Multiband OFDM Alliance (MBOA, http://www.multibandofdm.org) draft vO.95. It consists of several Medium Access Slots (As an example, the number is shown as 256). Some Medium Access Slots (MAS) constitute beacon period (comprising of beacon slots corresponding to multiple devices) and remaining MASs constitute data period (comprising of data slots that may be used by different devices in the network to transmit data to other devices in the network), employs a superframe duration of 65,536 microsecond with 256 MASs, and each MAS is of 256 microsecond duration. Information about superframe is being broadcasted by each device in its broadcasted beacons, so neighbors of that device can use that information for further processing. The start time of the superframe is determined by the beginning of the beacon period and defined as the beacon period start time (BPST). Devices that belong to the same beacon period shall utilize the same BPST for the superframe. However, some of the devices may define a different time as their BPST. In such cases, 2 or more beacon groups may coexist for the device. MASs are numbered relative to this starting time. The devices shall transform the numbering of MASs of other beaconing periods into the time reference of their main beaconing period. A device can be part of several beacon periods but has to select one beacon period as its main beacon period. Devices shall utilize the same BPST for the superframe. MASs are numbered relative to this starting time. All devices shall hear the beacon period at the start of the superframe and shall be time synchronized. MBOA-MAC in its present form has defined two modes of operation, active mode and hibernating mode. In active mode the device can either be in awake state or in sleep state. In awake state the device's transmitter and receivers are fully powered using more power even if they are not currently transmitting or receiving (idle condition). In the sleep state the device has powered down its transmitter and receiver circuitry and is using minimum power. In the active mode, devices switch between awake and sleep state depending on the data reservations already announced during the beacon period. The second power saving mechanism is where devices announce that they want to go to Hibernation mode. Devices that are going into hibernate mode announce in their beacon that they will be in hibernation for a certain number of superframes, during which they will be in deep sleep mode; they will not send or receive beacons or any other traffic; or will not try to listen any other traffic. Other devices in its BG will note this announcement and continue to include those devices in their BPOIE until the mentioned wakeup interval. Also, devices in the BG will maintain information in their local database about devices that are hibernating and will defer communication to them until they power on and start sending beacons. The stated medium access control mechanism can be used for communication of internet protocol traffic. One of the work group named WiNET of WiMedia Alliance (www.wimedia.org) is involved in standardization of this architecture. WiNET version 0.63 defines a protocol adaptation layer (PAL) for IPv6 and IPv4 to work over MBOA MAC-PHY. WiNET devices can connect to any other network outside WPAN via any WiNET based gateway or bridge device. According to current art explained in Indian patent application no. 553/CHE/2004, each device could be a WiNET device can be periodically awake during its local wakeup time. That information can be useful by all neighboring devices which are planning to communicate with other device. Similarly all WiNET devices can be awake during their periodic global wakeup time. That information can be useful by all devices for functions like device discovery etc. During this time all devices will be awake and any global information can be broadcasted, for e.g. change in period of local or global wakeup time. Global wakeup time can be broadcasted by gateway or bridge device. The present state of art in this field, has certain limitations, namely, there is no mechanism to announce local wakeup period and global wakeup period for the devices. Currently the mechanism, as defined in current art, can suffer from following limitations: 1. A device can go in hibernation mode and become awake depending on its own decision making parameters; or it can be awake for one or more superframes periodically, so other device want to communicate can use that information and can be awake for same superframe. There is no method to communicate to other devices this period (called "local wakeup superframe") in number of superframes, when device will be definitely awake in that superframe. 2. All devices can go in hibernation mode and become awake depending on their own decision making parameters; or they can be awake for one or more superframes periodically at same time in synchronized manner, so all devices can perform functions like device discovery and broadcast of other information from upper layer, which can be received by all devices, because all device will be awake in that superframe. There is no method to communicate to other devices this period (called "global wakeup superframe") in number of superframes, when all device will be definitely awake in that superframe. SUMMARY OF THE INVENTION The primary object of the invention is therefore to provide a system and method for announcement of local wakeup superframe and global wakeup superframe for the UWB wireless personal area networks, which are based on wireless ad-hoc networks, in a decentralized network topology. It is another object of the invention to provide a mechanism where devices can broadcast local wakeup superframe and period when it will be repeated. It is another object of the invention to provide a mechanism where one or more device can broadcast global wakeup superframe and period when it will be repeated. It is another object of the invention to provide a mechanism for providing facility for all devices to be awake during a known superframe, so they can perform functions like device discovery, broadcast of upper layer data, etc. The present invention relates to a system that allows an improved medium access control in the Wireless Personal Area Networks based on mobile ad-hoc networks in decentralized and distributed manner with upper layer as IPv4 or IPv6. The present invention comprises of system and method which would solve the problems associated with current art, in the following manner: 1. An information element called Global Wakeup Superframe IE is used to advertise global wakeup superframe and period of repetition. 2. An information element called Local Wakeup Superframe IE is used to advertise local wakeup superframe and period of repetition. Accordingly, the invention provides a mechanism where devices can broadcast local wakeup superframe and period when it will be repeated. Accordingly, the invention provides a mechanism where one or more device can broadcast global wakeup superframe and period when it will be repeated. Accordingly, the invention provides a mechanism for providing facility for all devices to be awake during a known superframe, so they can perform functions like device discovery, broadcast of upper layer data and etc. Accordingly, this invention explains a method for announcement of local wakeup superframe by local wakeup superframe IE. A device needs to be definitely awake during Local wake superframe periodically. If device is awake between two local wakeup superframes, then the IE provides the information about local wakeup superframe offset in number of superframes from current superframe. Accordingly, this invention explains a method for announcement of global wakeup superframe by global wakeup superframe IE. All devices should be awake during global wakeup superframe periodically. If the device, which is announcing, is awake between two global wakeup superframes, then the IE provides the information about global wakeup superframe offset in number of superframes from current superframe. Accordingly, this invention explains a method for wake period announcement in wireless networks using Local wakeup superframe IE comprising the steps of: announcing period of wakeup in number of superframes in LWS period field of LWS IE by the device; setting countdown field as (period - 1) superframe initially by the device; decrementing countdown field by one on each superframe by the said device and said device entering awake stage when countdown reaches to zero; starting countdown again after reaching to zero with (period - 1) from next superframe after local wakeup superframe by the said device; and transmitting LWS IE if it is not in hibernation mode by the device. Accordingly, this invention explains a method for wake period announcement in wireless networks using global wakeup superframe(GWS) IE comprising the steps of: announcing period of wakeup in number of superframes in GWS period field of GWS IE, for all devices communicating with itself by the said device; setting countdown field as (period - 1) superframe initially by the device; decrementing countdown field by one on each superframe by the device and said device and all other devices communicating with it entering awake stage when countdown reaches to zero; starting countdown again after reaching to zero with (period - 1) from next superframe after global wakeup superframe by the device;and transmitting GWS IE during global wakeup superframe by the device. Accordingly, this invention explains a system for wake period announcement in wireless networks using Local wakeup superframe IE comprising : means for announcing period of wakeup in number of superframes in LWS period field of LWS IE by the device; means for setting countdown field as (period - 1) superframe initially by the device; means for decrementing countdown field by one on each superframe by the said device and said device entering awake stage when countdown reaches to zero; means for starting countdown again after reaching to zero with (period - 1) from next superframe after local wakeup superframe by the said device; and means for transmitting LWS IE if it is not in hibernation mode by the device. Accordingly, this invention explains a method for wake period announcement in wireless networks using global wakeup superframe(GWS) IE comprising: means for announcing period of wakeup in number of superframes in GWS period field of GWS IE, for all devices communicating with itself by the said device; means for setting countdown field as (period - 1) superframe initially by the device; means for decrementing countdown field by one on each superframe by the device and said device and all other devices communicating with it entering awake stage when countdown reaches to zero; means for starting countdown again after reaching to zero with (period - 1) from next superframe after global wakeup superframe by the device; and means for transmitting GWS IE during global wakeup superframe by the device. Some of the other objects, features and advantages of the present invention will be more apparent from the ensuing description of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 illustrates the WPAN as a decentralized and distributed ad-hoc network system and range of all devices. Figure 2 illustrates the superframe structure in current art, which includes MASs and a dynamic beacon period (i.e. a BP with dynamic length). Figure 3 illustrates the Local Wakeup Superframe Information Element. Figure 4 illustrates the Global Wakeup Superframe Information Element. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system that allows an improved medium access control in the decentralized Wireless Personal Area Networks based on mobile ad-hoc networks. Accordingly, the invention provides a mechanism where devices can broadcast information about local wakeup superframe and period when it will be repeated. Accordingly, the invention provides a mechanism where one or more device can broadcast information about global wakeup superframe and period when it will be repeated. Accordingly, the invention provides a mechanism for providing facility for all devices to be awake during a known superframe, so they can perform functions like device discovery, broadcast of upper layer data and etc. The subsequent subsections describe the entity to effect the invention: 1. Local wakeup superframe IE Local wakeup superframe IE contains the information about local wakeup superframe and its period of repetition. The field LWS period, in number of superframe, is period of repetition of LWS. During LWS, the device will definitely be awake. Device will be awake for one or more number of superframes. The value of LWS can be one or many superframes, depending upon device's local needs and requirements. Device may or may not be awake between two local wakeup superframes. LWS countdown field announces offset of LWS from current superframe. It says that device will be definitely awake after countdown number of superframe from current superframe. 2. Global wakeup superframe IE Global wakeup superframe IE contains the information about global wakeup superframe and its period of repetition. The field GWS period, in number of superframes, is period of repetition of GWS. During GWS all devices should be awake. Device will be awake for one or more number of superframes. The value of GWS can be one or many superframes, depending upon device's local needs and requirements. Device may or may not be awake between two global wakeup superframes. GWS countdown field announces offset of GWS from current superframe. It says that device will be definitely awake after countdown number of superframe from current superframe. The subsequent subsections describe the operations to effect the invention: 1. Rules for usage of Local wakeup superframe IE Following are the invented steps provide the information about rules for usage of local wakeup superframe IE. — Device announces its period of wakeup (in number of superframes) in LWS period field of LWS IE. — The device sets Countdown field as (period - 1) superframe initially. — The device decrements countdown field by one on each superframe. — When countdown reaches to zero, the device has to be awake. — The device starts countdown again after reaching to zero with (period - 1) from next superframe after local wakeup superframe. — The device may or may not transmit LWS IE between two local wakeup superframes. — The device should transmit LWS IE if it is not in hibernation mode. — The device shall transmit LWS IE during global wakeup superframe. — The device can change LWS period during global wakeup superframe. 2. Rules for usage of Global wakeup superframe IE Following are the invented steps provide the information about rules for usage of global wakeup superframe IE. — Device announces its period of wakeup (in number of superframes) in GWS period field of GWS IE, for all devices communicating with itself. — The device sets Countdown field as (period - 1) superframe initially. — The device decrements countdown field by one on each superframe. — When countdown reaches to zero, the device acting as gateway or bridge, which is sending GWS IE, has to be awake and all other devices communicating with it should be awake. — The device starts countdown again after reaching to zero with (period - 1) from next superframe after global wakeup superframe. — The device may or may not transmit GWS IE between two global wakeup superframes. — The device should transmit GWS IE if it is not in hibernation mode. — The device shall transmit GWS IE during global wakeup superframe. — The device can change GWS period during global wakeup superframe. Using the embodiments of the invention, it is possible for a device to advertise local wakeup superframe and global wakeup superframe; also it will able to synchronize wakeup periods with other devices in neighborhood. It will also be obvious to those skilled in the art that other control methods and apparatuses can be derived from the combinations of the various methods and apparatuses of the present invention as taught by the description and the accompanying drawings and these shall also be considered within the scope of the present invention. Further, description of such combinations and variations is therefore omitted above. It should also be noted that the host for storing the applications include but not limited to a microchip, microprocessor, handheld communication device, computer, rendering device or a multi function device. 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 therefrom. GLOSSARY OF TERMS AND DEFINITONS THEREOF BG: Beacon Group BP: Beacon Period BPOIE: Beacon Period Occupancy Information Element BPST: Beacon Period Start Time GWS: Global Wakeup Superframe IE: Information Element IEEE: Institute of Electrical and Electronics Engineers IPv4: Internet Protocol Version 4 IPv6: Internet Protocol Version 6 LWS: Local Wakeup Superframe MAC: Medium Access Control MAS: Medium Access Slot MBOA: Multi Band OFDM Alliance OFDM: Orthogonal Frequency Division Multiplexing PAL: Protocol Adaptation Layer PHY: Physical Layer UWB: Ultra Wide Band WPAN: Wireless Personal Area Network WE CLAIM 1. A method for wake period announcement in wireless networks using Local wakeup superframe IE comprising the steps of: announcing period of wakeup in number of superframes in LWS period field of LWS IE by the device; setting countdown field as (period - 1) superframe initially by the device; decrementing countdown field by one on each superframe by the said device and said device entering awake stage when countdown reaches to zero; starting countdown again after reaching to zero with (period - 1) from next superframe after local wakeup superframe by the said device; and transmitting LWS IE if it is not in hibernation mode by the device. 2. A method as claimed in claim 1 wherein the device may or may not transmit LWS IE between two local wakeup superframes. 3. A method as claimed in claim 1 wherein the device transmits LWS IE during global wakeup superframe. 4. A method as claimed in claim 1 wherein the device can change LWS period during global wakeup superframe. 5. A method for wake period announcement in wireless networks using global wakeup superframe(GWS) IE comprising the steps of: announcing period of wakeup in number of superframes in GWS period field of GWS IE, for all devices communicating with itself by the said device; setting countdown field as (period - 1) superframe initially by the device; decrementing countdown field by one on each superframe by the device and said device and all other devices communicating with it entering awake stage when countdown reaches to zero; starting countdown again after reaching to zero wittt (period - 1) from next superframe after global wakeup superframe by the device;and transmitting GWS IE during global wakeup superframe by the device. 6. A method as claimed in claim 1 wherein the device may or may not transmit GWS IE between two global wakeup superframes. 7. A method as claimed in claim 1 wherein the device transmits GWS IE if it is not in hibernation mode. 8. A method as claimed in claim 1 wherein the device can change GWS period during global wakeup superframe. 9. A method as claimed in claim 1 wherein the device can advertise local wakeup superframe and global wakeup superframe and synchronize wakeup periods with other devices in neighborhood. 10. A method for wake period announcement in wireless networks allowing an improved medium access control in the decentralized Wireless Personal Area Networks based on mobile ad-hoc networks by a mechanism where devices can broadcast information about local/global wakeup superframe and period when it will be repeated. 11. A method as claimed in claim 10 wherein Local wakeup superframe IE contains the information about local wakeup superframe and its period of repetition. 12. A method as claimed in claim 10 wherein during Local wakeup superframe LWS, the device can be awake for one or more number of superframes. 13. A method as claimed in claim 10 wherein the value of LWS can be one or many superframes, depending upon device's local needs and requirements where the device may or may not be awake between two local wakeup superframes. 14. A method as claimed in claim 10 wherein LWS countdown field announces offset of LWS from current superframe which indicates that device is definitely awake after countdown number of superframe from current superframe. 15. A method as claimed in claim 10 wherein Global wakeup superframe (GWS) IE contains the information about global wakeup superframe and its period of repetition where the field GWS period, in number of superframes, is period of repetition of GWS. 16. A method as claimed in claim 10 wherein during GWS all devices can be awake and the device can be awake for one or more number of superframes. 17. A method as claimed in claim 10 wherein the value of GWS can be one or many superframes, depending upon device's local needs and requirements where the device may or may not be awake between two global wakeup superframes. 18. A method as claimed in claim 10 wherein GWS countdown field announces offset of GWS from current superframe which says that device will be definitely awake after countdown number of superframe from current superframe. 19. A system for wake period announcement in wireless networks using Local wakeup superframe IE comprising : means for announcing period of wakeup in number of superframes in LWS period field of LWS IE by the device; means for setting countdown field as (period - 1) superframe initially by the device; means for decrementing countdown field by one on each superframe by the said device and said device entering awake stage when countdown reaches to zero; means for starting countdown again after reaching to zero with (period - 1) from next superframe after local wakeup superframe by the said device; and means for transmitting LWS IE if it is not in hibernation mode by the device. 20. A system for wake period announcement in wireless networks using global wakeup superframe(GWS) IE comprising: means for announcing period of wakeup in number of superframes in GWS period field of GWS IE, for all devices communicating with itself by the said device; means for setting countdown field as (period - 1) superframe initially by the device; means for decrementing countdown field by one on each superframe by the device and said device and all other devices communicating with it entering awake stage when countdown reaches to zero; means for starting countdown again after reaching to zero with (period - 1) from next superframe after global wakeup superframe by the device; and means for transmitting GWS IE during global wakeup superframe by the device. 21. A method for wake period announcement in wireless networks substantially described particularly with reference to the accompanying drawings. 22. A system for wake period announcement in wireless networks substantially described particularly with reference to the accompanying drawings. Dated this 5th day of July 2006

Documents:

0883-che-2005-abstract.pdf

0883-che-2005-claims.pdf

0883-che-2005-correspondnece-others.pdf

0883-che-2005-description(complete).pdf

0883-che-2005-description(provisional).pdf

0883-che-2005-drawings.pdf

0883-che-2005-form 1.pdf

0883-che-2005-form 26.pdf

0883-che-2005-form 5.pdf

883-CHE-2005 AMENDED PAGES OF SPECIFICATION 14-10-2013.pdf

883-CHE-2005 AMENDED CLAIMS 14-10-2013.pdf

883-CHE-2005 CORRESPONDENCE OTHERS 18-10-2013.pdf

883-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 14-10-2013.pdf

883-CHE-2005 FORM-1 14-10-2013.pdf

883-CHE-2005 FORM-13 19-06-2006.pdf

883-CHE-2005 OTHER PATENT DOCUMENT 14-10-2013.pdf

883-CHE-2005 POWER OF ATTORNEY 14-10-2013.pdf

883-CHE-2005 POWER OF ATTORNEY 18-10-2013.pdf

883-CHE-2005 FORM-13 14-10-2013.pdf