CLIAMS:We claim:
1. A system for providing coexistence between a first radio module and a second radio module, wherein said system is configured to:
select a channel allocated to said first radio module for operation of said second radio module by said second radio module;
request said first radio module for reservation of said channel for operation of said second radio module;
allocate said channel for operation of said second radio module by said first radio module in response to said request; and
relinquish said channel after completing operation of said second radio module in said channel by said second radio module.
2. The system as in claim 1, wherein said first radio module is a Wireless Local Area Network Access Point (WLAN AP).
3. The system as in claim 1, wherein said second radio module is a Wireless Personal Access Network (WPAN) coordinator which comprises WPAN radio and WLAN radio.
4. The system as in claim 3, wherein said second radio module comprises at least one second radio device and operation of said second radio module refers to packet transmission by said at least one second radio device in said channel allocated by said first radio module.
5. The system as in claim 1, wherein said system is further configured to select said channel for operation of said second radio module based on minimum number of first radio devices connected to said first radio module.
6. The system as in claim 1, wherein said second radio module is configured to request said first radio module for reservation of said channel for operation of said second radio module in one of: Contention Period (CP), Contention Free Period (CFP) of a superframe provided by said first radio module.
7. The system as in claim 6, wherein said request comprises sending Request to Send-Ultra Low Power (RTS-ULP) frame during said CP by said second radio module to said first radio module.
8. The system as in claim 7, wherein said RTS-ULP comprises ULP allocation vector (UAV) field to indicate channel duration for operation of said second radio module.
9. The system as in claim 1, wherein first radio module is configured to allocate said channel for operation of said second radio module by sending Clear to Send-Ultra Low Power (CTS-ULP) frame in response to said RTS-ULP sent by said first radio module during said CP of said superframe.
10. The system as in claim 9, wherein said CTS-ULP comprises said UAV allocation field to indicate granted channel reservation duration for operation of said second radio module during said CP.
11. The system as in claim 6, wherein said request comprises sending ADD Traffic Streams-ULP (ADDTS-ULP) request frame by said second radio module for said channel reservation during said CFP of said superframe provided by said first radio module, wherein said ADD-TS request frame comprises Traffic Specification (TSPEC).
12. The system as in claim 1, wherein said first radio module is further configured to allocate said channel for operation of said second radio module by sending ADDTS-ULP response frame to said second radio module in response to said ADDTS-ULP request sent by said second radio module during said CFP.
13. The system as in claim 1, wherein said second radio module is further configured to wait for a beacon frame from said first radio module after successful channel reservation, further said second radio module is configured to locate said CFP and waits for CF-Poll frame from said first radio module.
14. The system as in claim 13, wherein said second radio module is further configured to receive said CF-Poll frame from said first radio module with a Transmit Opportunity (TXOP) value allocated to said second radio module indicating duration for a granted operation of said second radio module.
15. The system as in claim 1, wherein said first radio module is configured to allow said at least one second radio device to perform said packet transmission in said channel during one of: said CP, said CFP.
16. A method for providing coexistence between a first radio module and a second radio module, wherein said method comprises:
selecting a channel allocated to said first radio module for operation of said second radio module by said second radio module;
requesting said first radio module for reservation of said channel to operation of said second radio module;
allocating said channel for operation of said second radio module by said first radio module in response to said request; and
relinquishing said channel after completing operation of said second radio module in said channel by said second radio module.
17. The method as in claim 16, wherein said first radio module is a Wireless Local Area Network Access Point (WLAN AP).
18. The method as in claim 16, wherein said second radio module is a Wireless Personal Access Network (WPAN) coordinator which comprises WPAN radio and WLAN radio.
19. The method as in claim 16, wherein said second radio module comprises at least one second radio device and a operation of said second radio module refers to packet transmission by said at least one second radio device in said channel allocated by said first radio module.
20. The method as in claim 16, wherein said method comprises selecting said channel for operation of said second radio module based on minimum number of first radio devices connected to said first radio module.
21. The method as in claim 16, wherein said method comprises requesting said first radio module for reservation of said channel by said second radio module for operation of said second radio module in one of: Contention Period (CP), Contention Free Period (CFP) of a superframe provided by said first radio module.
22. The method as in claim 21, wherein said request comprises sending Request to Send-Ultra Low Power (RTS-ULP) frame during said CP by said WPAN coordinator to said first radio module.
23. The method as in claim 22, wherein said RTS-ULP comprises ULP allocation vector (UAV) field to indicate channel duration for operation of said second radio module.
24. The method as in claim 16, wherein method comprises allocating said channel by said first radio module for operation of said second radio module by sending Clear to Send-Ultra Low Power (CTS-ULP) frame in response to said RTS-ULP sent by said second radio module during said CP of said superframe.
25. The method as in claim 24, wherein said CTS-ULP comprises said UAV allocation field to indicate granted channel reservation duration for operation of said second radio module during said CP.
26. The method as in claim 22, wherein said request comprises sending ADD Traffic Streams-ULP (ADDTS-ULP) request frame by said second radio module for said channel reservation during said CFP of said superframe provided by said first radio module, wherein said ADD-TS request frame comprises Traffic Specification (TSPEC).
27. The method as in claim 16, wherein said method comprises allocating said channel by said first radio module for operation of said second radio module by sending ADDTS-ULP response frame to said second radio module in response to said ADDTS-ULP request sent by said second radio module during said CFP.
28. The method as in claim 16, wherein said method further comprises waiting for a beacon frame from said first radio module by said second radio module after successful channel reservation, further said second radio module locates said CFP and waits for CF-Poll frame from said first radio module.
29. The method as in claim 28, wherein said method further comprises receiving said CF-Poll frame by said second radio module from said WLAN AP with a Transmit Opportunity (TXOP) value allocated to said second radio module indicating duration for a granted operation of said second radio module.

30. The method as in claim 16, wherein said method further comprises allowing at least one said second radio device to perform said packet transmission in said channel during one of: said CP, said CFP.
Dated: 12th day of August, 2013 Signature:
Vikram Pratap Singh Thakur
Patent Agent ,TagSPECI:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“A system and method to allow coexistence of WPAN operation in WiFi channel”

APPLICANTS:

Name : Samsung India Software Operations Pvt Ltd

Nationality : Indian

Address : Bagmane Lakeview, Block B, No. 66/1,
Bagmane Tech Park, CV Raman Nagar,
Byrasandra, Bangalore- 560093
The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION
[001] The present invention relates to communication between two different networks sharing the same frequency spectrum for their network operations and more particularly to collaborative coexistence of WPAN network with WLAN network, in which a WPAN coordinator communicates with WLAN AP for WPAN network operation.

BACKGROUND OF INVENTION
[002] Wireless communication between multiple electronic devices has been increasing as the benefits and convenience of wireless communication has become more preferred over wired communication. Wireless Personal Area Network (WPAN) technologies such as Bluetooth, Zigbee operate in 2.4 GHz band and suffer from Wireless Local Area Network (WLAN) interference due to high transmission power characteristics of WLAN. Based on literature survey, ZigBee and WLAN device can experience interference rates of up to 58% when base lining the potential interference faced by ZigBee. Such a high interference caused by WLAN will severely affect the network performance of Zigbee network. Bluetooth employs Adaptive Frequency Hopping (AFH) to mitigate the WLAN interference. In AFH, a Bluetooth channel can be classified as good or bad, so that bad channels are avoided and replaced in the hopping sequence by pseudo-randomly selecting out of the remaining good channels. However, the AFH is not effective if the entire band is subject to interference from the WLAN device.
[003] High power WLAN transmissions can interfere with co-located WPAN networks. To avoid WLAN interference, WPAN networks can operate in a WPAN channel that does not overlap with WLAN network. However, WLAN networks are almost ubiquitous in homes, office buildings, and outdoors in urban areas and one WLAN system occupies 22 MHz of channel bandwidth in the 2.4GHz band. Hence, non-overlapping channel for a WPAN network cannot be guaranteed.
[004] One existing method tries to address the interference problem between sensor devices and WiFi devices by synchronizing clock globally among all the devices (sensor devices and WiFi devices). In this method, each time slot is divided to Frequency Hopping Spectrum (FHSS) slot (sensor network slot) and WiFi slot. To minimize WiFi packet drop, FHSS slot size is reduced. Arbitrarily reducing FHSS slot size will impact the Quality of Service (QoS) requirements of sensor networks. Also, sensors having Global Positioning System (GPS) or any solution for global synchronization are not a practical solution.
[005] In another existing method, a Zigbee gateway purposefully sends a Ready to send (RTS) frame with an invalid WiFi address to silent the WiFi stations from any transmission. And, allows Zigbee transmission during the set Network Allocation Vector (NAV) duration as specified by the RTS frame. This violates the WiFi protocol since the RTS frame must be destined to a WiFi node in the WiFi network.
[006] Some existing methods use the WLAN RTS/Clear to Send (CTS) frames for coordination between a WPAN coordinator and a WLAN Access Point (AP). However, RTS and CTS frames are not effective since RTS/CTS frames in WLAN networks are used for setting NAV and stations defer access to the channel for NAV duration. Duration field in the RTS frame is 2 octets and maximum duration that can be specified with RTS frame is 65.536 ms. So, the WLAN devices can defer access to the medium maximum for 65.53 ms. This is not sufficient for low-data rate WPAN operation where the session go as large as 100 ms. Also, RTS/CTS based NAV setting allows transmission of only one frame and station must release the channel after successful transmission of the frame. WPAN operation needs exchange of many frames between WPAN coordinator and WPAN devices. In the RTS-> CTS-> Packet-> ACK sequence, the packet must be a WLAN Packet. However WPAN network intend to transmit a WPAN packet.
[007] Another existing method use an overlay protocol for WLAN and PAN which requires dual radios (both WLAN and WPAN) for all the devices in both explicit as well as implicit signaling. The PAN overlay frames are exchanged between WLAN Access Point (AP), WPAN coordinator and the sensor devices. This leads to high cost when using dual radios for all the devices. Also, exchange of PAN overlay frames for sensor networks is an overhead and consumes more power at the sensor devices.

OBJECT OF INVENTION

[008] The principal object of the embodiments herein is to system and method providing coexistence between a Wireless Personal Area Network (WPAN) and Wireless Local Area Network (WLAN), where the WPAN and WLAN share the same spectrum in an unlicensed band for network operations.
[009] Another object of the invention is to provide coexistence of WPAN in Contention Period (CP) and Contention Free Period (CFP) of WLAN.
[0010] Another object of the invention is to provide new frames for the coordination between a WPAN coordinator and a WLAN Access Point (AP).

SUMMARY

[0011] Accordingly the invention provides a system for providing coexistence between a first radio module and a second radio module, wherein the system is configured to select a channel allocated to the first radio module for operation of the second radio module by the second radio module. The system is further configured to request the first radio module for reservation of the channel for operation of the second radio module. Further the system is configured to allocate the channel for operation of the second radio module by the first radio module in response to the request. Furthermore the system is configured to relinquish the channel after completing operation of the second radio module in the channel by the second radio module.
[0012] Accordingly the invention provides a method for providing coexistence between a first radio module and a second radio module, wherein the method comprises selecting a channel allocated to the first radio module for operation of the second radio module by the second radio module. The method further comprises requesting the first radio module for reservation of the channel to operation of the second radio module. Further the method comprises allocating the channel for operation of the second radio module by the first radio module in response to the request. Furthermore the method comprises relinquishing the channel after completing operation of the second radio module in the channel by the second radio module.
[0013] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[0014] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0015] FIG. 1 illustrates an example channel selection for WPAN operation, according to embodiments as disclosed herein;
[0016] FIG. 2 illustrates a coexistence scenario between a WPAN and WLAN, according to embodiments as disclosed herein;
[0017] FIG. 3 illustrates a WPAN and a WLAN radio architecture, according to embodiments as disclosed herein;
[0018] FIG. 4 illustrates a timing diagram showing coexistence between a WPAN Coordinator and a WLAN AP in contention period, according to embodiments as disclosed herein;
[0019] FIG. 5 illustrates a timing diagram showing coexistence between a WPAN and a WLAN in contention period, when WLAN AP is in the mixed mode, according to embodiments as disclosed herein;
[0020] FIG. 6 illustrates a flow diagram explaining coexistence of a WPAN coordinator and a WLAN AP in the contention access period of WLAN Superframe, according to embodiments as disclosed herein;
[0021] FIG. 7 illustrates a RTS-ULP frame format, according to embodiments as disclosed herein;
[0022] FIG. 8 illustrates a CTS-ULP frame format, according to embodiments as disclosed herein;
[0023] FIG. 9 illustrates a timing diagram showing coordination between a WPAN coordinator and a WLAN AP in the contention free period of WLAN AP, according to embodiments as disclosed herein; and
[0024] FIG. 10 illustrates a table showing updated QoS Action field format, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION
[0025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0026] The labels first and second described herein are used only for illustrative purpose and do not limit the scope of the invention, which is defined only by the claims. The terms first and second are generally used, unless otherwise indicated, to illustrate the use of similar or substantially similar components and it is to be understood that other example embodiments are not limited thereto.
[0027] The embodiments herein achieve a system and method for collaborative coexistence of first radio network with a second radio network. The second radio network requests the first radio network to use a channel allocated to the first radio network for operation of the second radio network.
[0028] In an embodiment, the first radio network can be a Wireless Local Area Network (WLAN) which comprises a first radio module such as a WLAN Access Point (WLAN AP) to which plurality of first radio devices such as WiFi devices are connected.
[0029] In an embodiment, the second radio network can be Wireless Personal Area Network (WPAN) which comprises a second radio module such as a WPAN coordinator to which plurality of second radio devices such as WPAN devices are connected.
[0030] The proposed method provides coexistence between a WPAN coordinator module (second radio module) and WLAN Access Point (AP) module (first radio module). The WPAN coordinator communicates with the WLAN AP for WPAN operation.
[0031] Throughout the description the terms first radio module and WLAN AP are used interchangeably.
[0032] Throughout the description the terms second radio module and WPAN coordinator are used interchangeably.
[0033] In an embodiment, the WPAN coordinator acts a hub to plurality of WPAN devices. In an embodiment, the WPAN devices can be Bluetooth devices, Zigbee devices, Body Area Network sensors or any other short range communication devices.
[0034] In an embodiment, the WLAN AP acts as a hub to plurality of WiFi devices (Stations). In an embodiment, the stations can be a mobile phone, smart phone, Laptop, Tablet, or any other wireless devices having WiFi module.
[0035] Referring now to the drawings, and more particularly to FIGS. 1 through 10, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0036] FIG. 1 illustrates an example channel selection for WPAN operation, according to embodiments as disclosed herein. In an embodiment, the proposed method supports coexistence between a wireless network (such as WPAN) and wireless local area network (WLAN) in an unlicensed band, where the WPAN and WLAN share the same spectrum in the unlicensed band for network operations. Generally, WPAN networks scan the unlicensed band to start the network operation in a WLAN interference free channel. However, due to large bandwidth requirement in WLAN, it is difficult to always guarantee a WLAN interference free channel for WPAN. In such a situation, WPAN and WLAN need to share the same channel resources for their respective operation. To select a channel for network operation allocated to the WLAN AP, WPAN coordinator scans all the channels in the Industrial, Scientific and Medical (ISM) band. WPAN coordinator selects the WLAN interference free channel for WPAN operation. The WPAN coordinator selects a WLAN channel (22 MHz in 2.4 GHz ISM band) with minimum number of WLAN networks for WPAN operation when the WLAN interference free channel is not available in the ISM band. The proposed method is a collaborative method, where the WPAN coordinator and WLAN AP share the same WLAN channel, coordinate the channel access and avoid interference caused by one network to the other network. The figure shows the active WiFi channels and the selected WPAN channels in WiFi channel.
[0037] FIG. 2 illustrates a coexistence scenario between a WPAN and WLAN, according to embodiments as disclosed herein. The figure depicts the two-way communication between a WPAN coordinator 200 and WLAN AP 201. The WPAN coordinator comprises plurality of nodes (node 1-node 6). In an embodiment, the nodes refer to the WPAN devices connected to the WPAN coordinator 200. For example, the WPAN device can be a Bluetooth device, Zigbee device, Body area network sensors or any other short range communication device. The WLAN AP 201 comprises plurality of stations (STA 1- STA 6). In an embodiment, the stations can be WiFi devices. For example, the station can be a laptop, smart phone, tablet or any other electronic device capable of communicating with WLAN AP. To get the WiFi channel for WPAN operation, the WPAN coordinator 200 sends the request to the WLAN AP 201 for WPAN operation. In response, based on the availability of the channel, the WLAN AP 201 sends the response to the WPAN coordinator. Hence, there is two-way communication between the WPAN coordinator and WLAN AP. Generally, there are two modes in WLAN: Ad-Hoc mode and Infrastructure mode. In the ad-hoc mode, WLAN operates in the contention mode exclusively, requiring each WLAN node to contend to access the channel for each frame transmitted. In the infrastructure mode, WLAN alternates between contention period (CP) and contention free period (CFP). During the CFP, the WLAN AP can control the access to the medium, thereby eliminating the need for contention during the CFP.
[0038] Proposed method addresses the coexistence of a WPAN and WLAN with both operating in the infrastructure mode.
[0039] FIG. 3 illustrates a WPAN and a WLAN radio architecture, according to embodiments as disclosed herein. The enable WPAN operation in WiFi channel, the WPAN coordinator 200 comprises both WPAN radio and complaint WLAN radio. There is a dual radio in the WPAN coordinator 200. The WPAN radio helps to exchange frames with WPAN devices and WLAN radio helps to exchange frames with the WLAN AP 201.
[0040] FIG. 4 illustrates a timing diagram showing coexistence between a WPAN Coordinator and a WLAN AP in contention period, according to embodiments as disclosed herein. After selection of an appropriate WLAN channel for WPAN operation, the WPAN coordinator 200 collaborates with WLAN AP 201 for WPAN operation as described below. The WPAN coordinator 200 has two modes: WPAN mode and WLAN mode (Ultra Low Power (ULP) mode). Whenever WPAN coordinator 200 wants to have a data session with its sensor devices, WPAN coordinator switches to WLAN mode and joins the WLAN network as the station (STA) or the WLAN device. After joining the WLAN network, WPAN coordinator 200 waits for beacon frame transmitted by WLAN STA and locates the contention period. In the contention access period, WPAN coordinator 200 access the channel following the contention access procedure defined in the IEEE 802.11 specification. After getting access to the channel, the WPAN coordinator 200 transmits Request to Send-Ultra Low Power (RTS-ULP) frame to the WLAN AP 201 and waits for Clear to Send-Ultra Low Power (CTS-ULP) frame from the WLAN AP 201. Upon receiving the RTS-ULP frame, WLAN AP 201 waits for Short Inter-Frame Space (SIFS) and responds with CTS-ULP frame. Then the WLAN AP 201 allows the commencement of WPAN operation in the occupied WLAN channel. RTS-ULP frame and CTS-ULP frames contain a field with ULP allocation vector (UAV), wherein UAV specifies the duration of ULP operation (ULP data transfer) in the WLAN channel as requested by the WPAN coordinator 200.
[0041] The WLAN devices that receive RTS-ULP frame and CTS-ULP frame set their UAV counter and defer access to the channel for the UAV duration.
[0042] After receiving a CTS-ULP frame, the WPAN coordinator 200 switches to the WPAN radio mode and begins WPAN operation with its sensor device. For example, the sensor device can be a Bluetooth device, and on receiving the CTS-ULP frame the Bluetooth transmission or reception can start in the WiFi channel allocated by the WiFi AP 201.
[0043] When the UAV duration expires, WPAN coordinator 200 releases the WLAN channel for WLAN operation. The WPAN coordinator 200 switches back to WLAN radio mode when it wants to have a WPAN session again and repeats the above mentioned procedure.
[0044] FIG. 5 illustrates a timing diagram showing coexistence between a WPAN and a WLAN in contention period, when WLAN AP is in the mixed mode, according to embodiments as disclosed herein. In an embodiment, the mixed mode includes RTS-ULP and CTS-ULP frames. In the mixed mode operation, the WLAN AP 201 is associated with new WLAN devices (which support proposed new frames RTS-ULP and CTS-ULP) as well as legacy WLAN devices in a Base Service Set (BSS) for coexistence between these new devices and legacy devices which do not support proposed new frames RTS-ULP and CTS-ULP. After locating the beacon frame and contention period from WLAN AP 201, the WPAN coordinator 200 transmits RTS-ULP frame to the WLAN AP 201. Upon receiving RTS-ULP frame from WPAN coordinator 200, WLAN AP 201 sends CTS frame to the WPAN coordinator 200. Note that RTS-ULP frame contains UAV duration as requested by the WPAN coordinator 200 and CTS NAV duration is limited by 2 octet duration field values. Whenever UAV duration is greater than the maximum NAV duration, WLAN AP 201 sets the maximum NAV duration in the CTS frame when responding to the RTS-ULP frame. WLAN devices in the mixed mode defer the access to the channel for NAV duration. WPAN coordinator 200 commences WPAN operation in the set NAV duration and relinquishes channel after expiration of the NAV duration. Further, the WPAN coordinator 200 switches back to WLAN radio mode when it wants to have a WPAN session again and repeats the procedure.
[0045] FIG. 6 illustrates a flow diagram explaining coexistence of a WPAN coordinator and a WLAN AP in the contention access period of WLAN Superframe, according to embodiments as disclosed herein. In the flow diagram, the WLAN AP is referred as WiFi AP. Initially, the WPAN coordinator 200 switches (601) to WiFi radio mode. The WPAN coordinator 200 receives (602) the beacon from WiFi AP and locate contention period. After receiving the beacon from the WiFi AP, the WPAN coordinator 200 contends (603) with WiFi AP to transmit RTS-ULP frame. Further, the WPAN coordinator 200 determines (604) whether the channel access of WiFi AP is successful. If the channel access it not successful, then the WPAN coordinator 200 again contends to transmit the RTS-ULP frame as described in step 603. If the channel access is successful, then the WPAN coordinator 200 directly transmits (605) the RTS-ULP frame to the WiFi AP 201. The WPAN coordinator 200 waits for the SIFS period and checks whether the (606) for the CTS-ULP frame from the WiFi AP 201is received or not. If the WPAN coordinator 200 does not receive the CTS-ULP frame from the WiFi AP 201, then the WPAN coordinator again contends to transmit RTS-ULP frame as described in step 603. If the WPAN coordinator 200 receives the CTS-ULP frame from the WiFi AP 201, then the WPAN coordinator switches (607) to WPAN radio mode and start WPAN operation. For example, the WPAN operation can be any Bluetooth transmission which can be performed on the WiFi channel. Both the RTS-ULP and CTS-ULP frame includes the UAV specifying the duration of ULP operation. The WPAN coordinator 200 receives the UAV along with the CTS-ULP frame from the WiFi AP 201. After the expiration of the UAV, the WPAN coordinator 200 relinquishes (608) WiFi channel and moves to the WPAN mode. In an embodiment, the WPAN coordinator 200 whenever wants to perform the WPAN operation can repeat from step 601 to step 608. The various actions in flow diagram 600 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 6 may be omitted.
[0046] FIG. 7 illustrates a RTS-ULP frame format, according to embodiments as disclosed herein. In a RTS-ULP frame, Receiver Address (RA) is the address of the WLAN AP 201, Transmitter Address (TA) is the address of the WPAN coordinator 200. The UAV duration in the RTS-ULP frame is the time in microseconds required to carry out a WPAN session, plus transmission time of one CTS frame, plus two SIFS intervals.
[0047] FIG. 8 illustrates a CTS-ULP frame format, according to embodiments as disclosed herein. In a CTS-ULP frame, RA field is copied from the TA field of the immediately received RTS-ULP frame to which CTS-ULP is a response. The UAV duration valued in the CTS-ULP frame is in microseconds, required to carry out a WPAN session by WPAN coordinator 200, plus one SIFS interval. In frame control field, for RTS-ULP control frame, the type field value is 01 and the subtype field value is 0110 and for CTS-ULP control frame the type field value is 01 and the subtype field value is 0111.
[0048] WLAN devices compliant to the proposed method will possess mechanism to encode and process the proposed frames. However, legacy WLAN devices are not equipped to process such type of frames and will discard the RTS-ULP and CTS-ULP frames.
[0049] In an embodiment, the method provides coexistence between WPAN coordinator 200 and WLAN AP 201, when WLAN AP 201 operates in a mixed mode. In a mixed mode operation, WLAN AP 201 is associated with new WLAN devices as well as legacy WLAN devices in a BSS.
[0050] FIG. 9 illustrates a timing diagram showing coordination between a WPAN coordinator and a WLAN AP in the contention free period of WLAN AP, according to embodiments as disclosed herein. The WPAN coordinator 200 switches to the WLAN mode and gets associated with the BSS of WLAN AP 201. The WPAN coordinator 200 sends an Association Request frame to the WLAN AP 201. After the WLAN AP 201 receives the association request successfully, it responds with an Association Response frame back to the WPAN coordinator. After getting associated with WLAN AP, WPAN coordinator sends ADDTS-ULP Request command with a defined Traffic Specification (TSPEC). The TSPEC is derived from the QoS requirements and traffic characteristics of a WPAN session as decided by the WPAN coordinator 200. The WLAN AP transmits ADD Traffic Stream-Ultra Low Power (ADDTS-ULP) Response command in response to the ADDTS-ULP Request command. The WPAN coordinator 200 waits for the beacon frame transmitted by WLAN AP 201 and locates the contention free period. In the contention free period, WPAN coordinator 200 waits for CF-POLL frame from the WLAN AP 201. The CF-POLL frame from the WLAN AP 201 contains the value of Transmit Opportunity (TXOP) allocated to the WPAN coordinator 200. The TXOP is allocated to WPAN coordinator 200 based on TSPEC value communicated by WPAN coordinator 200 in the ADD Traffic Stream-Ultra Low Power (ADDTS-ULP) Request frame. After receiving the CF-POLL frame from the WLAN AP 201, the WPAN coordinator 200 switches to WPAN radio mode and carries out WPAN data session. The WPAN coordinator 200 relinquishes the WLAN channel after the allocated TXOP limit. Whenever the WPAN coordinator 200 wants to have a WPAN session, the WPAN coordinator 200 switches back to WLAN mode and waits for the beacon frame from WLAN AP 201 and waits for its turn in the next CFP.
[0051] FIG. 10 illustrates a table showing updated QoS Action field format, according to embodiments as disclosed herein. Two new frames, ADDTS-ULP request and ADDTS-ULP response frames are created under the Quality of Service (QoS) Action frame category for coexistence between WPAN network and WLAN network. The ADDTS-ULP Request frame is a new QoS Action frame under management frame category defined for the admission of WPAN coordinator 200 to the WLAN AP’s 201 polling list. The ADDTS-ULP Response frame is a new QoS Action frame under management frame category defined for the response of WLAN AP 201 to the WPAN coordinator’s 200 request.
[0052] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the elements. The elements shown in Figs. 2 and 3 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0053] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

STATEMENT OF CLAIMS
We claim:
1. A system for providing coexistence between a first radio module and a second radio module, wherein said system is configured to:
select a channel allocated to said first radio module for operation of said second radio module by said second radio module;
request said first radio module for reservation of said channel for operation of said second radio module;
allocate said channel for operation of said second radio module by said first radio module in response to said request; and
relinquish said channel after completing operation of said second radio module in said channel by said second radio module.
2. The system as in claim 1, wherein said first radio module is a Wireless Local Area Network Access Point (WLAN AP).
3. The system as in claim 1, wherein said second radio module is a Wireless Personal Access Network (WPAN) coordinator which comprises WPAN radio and WLAN radio.
4. The system as in claim 3, wherein said second radio module comprises at least one second radio device and operation of said second radio module refers to packet transmission by said at least one second radio device in said channel allocated by said first radio module.
5. The system as in claim 1, wherein said system is further configured to select said channel for operation of said second radio module based on minimum number of first radio devices connected to said first radio module.
6. The system as in claim 1, wherein said second radio module is configured to request said first radio module for reservation of said channel for operation of said second radio module in one of: Contention Period (CP), Contention Free Period (CFP) of a superframe provided by said first radio module.
7. The system as in claim 6, wherein said request comprises sending Request to Send-Ultra Low Power (RTS-ULP) frame during said CP by said second radio module to said first radio module.
8. The system as in claim 7, wherein said RTS-ULP comprises ULP allocation vector (UAV) field to indicate channel duration for operation of said second radio module.
9. The system as in claim 1, wherein first radio module is configured to allocate said channel for operation of said second radio module by sending Clear to Send-Ultra Low Power (CTS-ULP) frame in response to said RTS-ULP sent by said first radio module during said CP of said superframe.
10. The system as in claim 9, wherein said CTS-ULP comprises said UAV allocation field to indicate granted channel reservation duration for operation of said second radio module during said CP.
11. The system as in claim 6, wherein said request comprises sending ADD Traffic Streams-ULP (ADDTS-ULP) request frame by said second radio module for said channel reservation during said CFP of said superframe provided by said first radio module, wherein said ADD-TS request frame comprises Traffic Specification (TSPEC).
12. The system as in claim 1, wherein said first radio module is further configured to allocate said channel for operation of said second radio module by sending ADDTS-ULP response frame to said second radio module in response to said ADDTS-ULP request sent by said second radio module during said CFP.
13. The system as in claim 1, wherein said second radio module is further configured to wait for a beacon frame from said first radio module after successful channel reservation, further said second radio module is configured to locate said CFP and waits for CF-Poll frame from said first radio module.
14. The system as in claim 13, wherein said second radio module is further configured to receive said CF-Poll frame from said first radio module with a Transmit Opportunity (TXOP) value allocated to said second radio module indicating duration for a granted operation of said second radio module.
15. The system as in claim 1, wherein said first radio module is configured to allow said at least one second radio device to perform said packet transmission in said channel during one of: said CP, said CFP.
16. A method for providing coexistence between a first radio module and a second radio module, wherein said method comprises:
selecting a channel allocated to said first radio module for operation of said second radio module by said second radio module;
requesting said first radio module for reservation of said channel to operation of said second radio module;
allocating said channel for operation of said second radio module by said first radio module in response to said request; and
relinquishing said channel after completing operation of said second radio module in said channel by said second radio module.
17. The method as in claim 16, wherein said first radio module is a Wireless Local Area Network Access Point (WLAN AP).
18. The method as in claim 16, wherein said second radio module is a Wireless Personal Access Network (WPAN) coordinator which comprises WPAN radio and WLAN radio.
19. The method as in claim 16, wherein said second radio module comprises at least one second radio device and a operation of said second radio module refers to packet transmission by said at least one second radio device in said channel allocated by said first radio module.
20. The method as in claim 16, wherein said method comprises selecting said channel for operation of said second radio module based on minimum number of first radio devices connected to said first radio module.
21. The method as in claim 16, wherein said method comprises requesting said first radio module for reservation of said channel by said second radio module for operation of said second radio module in one of: Contention Period (CP), Contention Free Period (CFP) of a superframe provided by said first radio module.
22. The method as in claim 21, wherein said request comprises sending Request to Send-Ultra Low Power (RTS-ULP) frame during said CP by said WPAN coordinator to said first radio module.
23. The method as in claim 22, wherein said RTS-ULP comprises ULP allocation vector (UAV) field to indicate channel duration for operation of said second radio module.
24. The method as in claim 16, wherein method comprises allocating said channel by said first radio module for operation of said second radio module by sending Clear to Send-Ultra Low Power (CTS-ULP) frame in response to said RTS-ULP sent by said second radio module during said CP of said superframe.
25. The method as in claim 24, wherein said CTS-ULP comprises said UAV allocation field to indicate granted channel reservation duration for operation of said second radio module during said CP.
26. The method as in claim 22, wherein said request comprises sending ADD Traffic Streams-ULP (ADDTS-ULP) request frame by said second radio module for said channel reservation during said CFP of said superframe provided by said first radio module, wherein said ADD-TS request frame comprises Traffic Specification (TSPEC).
27. The method as in claim 16, wherein said method comprises allocating said channel by said first radio module for operation of said second radio module by sending ADDTS-ULP response frame to said second radio module in response to said ADDTS-ULP request sent by said second radio module during said CFP.
28. The method as in claim 16, wherein said method further comprises waiting for a beacon frame from said first radio module by said second radio module after successful channel reservation, further said second radio module locates said CFP and waits for CF-Poll frame from said first radio module.
29. The method as in claim 28, wherein said method further comprises receiving said CF-Poll frame by said second radio module from said WLAN AP with a Transmit Opportunity (TXOP) value allocated to said second radio module indicating duration for a granted operation of said second radio module.

30. The method as in claim 16, wherein said method further comprises allowing at least one said second radio device to perform said packet transmission in said channel during one of: said CP, said CFP.
Dated: 12th day of August, 2013 Signature:
Vikram Pratap Singh Thakur
Patent Agent

ABSTRACT
A system and method providing coexistence between a WPAN coordinator and WLAN Access Point (AP) is disclosed. The WPAN coordinator requests WLAN AP for WPAN operation in a selected WLAN channel. The WLAN AP responds with the allocated time limit for which the WPAN operation can be performed. After expiration of the allocated time limit, the WPAN coordinator relinquishes the channel to the WLAN AP. The method addresses the operation of the WPAN system in 2.4 GHz ISM band when a non-overlapping WPAN channel selection is infeasible.
FIG. 2