METHOD AND APPARATUS FOR SUPPORTING WIDEBAND AND MULTIPLE BANDWIDTH TRANSMISSION PROTOCOLS

• US 20120327870A1
• Filed: 06/21/2012
• Published: 12/27/2012
• Est. Priority Date: 06/24/2011
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Grandhi, Sudheer A., Anepu, Bhaskar M., Wang, Xiaofei
• Granted Patent: US 9,369,918 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 76/11 Allocation or use of connection identifiers
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

Enhanced protocols and devices may be used to alleviate loss of spectrum efficiency in wideband transmission. The protocols may implement a wideband transmission opportunity (TXOP) truncation where one or more of the channels involved in communication over the wideband are released. In one scenario, a wireless transmit/receive unit (WTRU) may obtain a TXOP for a 2 MHz bandwidth mode frame transmission with another device capable of operating in a 2 MHz bandwidth mode and a 1 MHz bandwidth mode. The WTRU may conduct a request-to-send (RTS)/clear-to-send (CTS) frame exchange in the second bandwidth mode, and truncate the TXOP by transmitting a contention free (CF)-End frame in the first and second bandwidth modes. In another scenario, an AP may obtain a TXOP for a 2 MHz bandwidth mode frame transmission with a WTRU capable of both 2 MHz and 1 MHz bandwidth modes.

Claims

1. An access point (AP) comprising:

a receiver configured to receive a first contention free (CF)-End frame on a primary channel, wherein the CF-End frame includes a bit that indicates whether a bandwidth value is set; and

a transmitter configured to transmit a second CF-End frame in response to the first CF-End frame, wherein, on a condition that the bit indicates that a bandwidth value is set, the second CF-End frame is transmitted on the primary channel and a non-primary channel of the indicated bandwidth, and wherein, on a condition that the bit indicates that a bandwidth value is not set, the second CF-End frame is transmitted at least on the primary channel.

2. The AP of claim 1, wherein the bit further indicates that a scrambling sequence is included in the first CF-End frame, wherein the scrambling sequence includes bandwidth information.

3. The AP of claim 1, wherein the first CF-End frame indicates a truncation of a wideband transmit opportunity (TXOP).

4. The AP of claim 1, wherein the transmitter is further configured to transmit the second CF-End frame after an inter-frame space duration.

5. The AP of claim 4, wherein the inter-frame space duration is a short inter-frame space (SIFS) duration.

6. A method for use in an access point (AP), the method comprising:

receiving a first contention free (CF)-End frame on a primary channel, wherein the CF-End frame includes a bit that indicates whether a bandwidth value is set; and

transmitting a second CF-End frame in response to the first CF-End frame, wherein, on a condition that the bit indicates that a bandwidth value is set, transmitting the second CF-End frame on the primary channel and a non-primary channel of the indicated bandwidth, and wherein, on a condition that the bit indicates that a bandwidth value is not set, transmitting the second CF-End frame at least on the primary channel.

7. The method of claim 6, wherein the primary channel is a 1 MHz channel within a 2 MHz bandwidth.

8. The method of claim 6, wherein the non-primary channel is a 1 MHz channel within a 2 MHz bandwidth.

9. The method of claim 6, wherein the bit further indicates that a scrambling sequence is included in the first CF-End frame, wherein the scrambling sequence includes bandwidth information.

10. The method of claim 6, wherein the first CF-End frame indicates a truncation of a wideband transmit opportunity (TXOP).

11. The method of claim 6, wherein the second CF-End frame is transmitted after an inter-frame space duration.

12. The method of claim 11, wherein the inter-frame space duration is a short inter-frame space (SIFS) duration.

13. A method for use in a first wireless transmit/receive unit (WTRU), the method comprising:

maintaining a first and second network allocation vector (NAV) counter;

receiving a contention free (CF)-End frame from a second WTRU, wherein the CF-End frame indicates truncation of a transmit opportunity (TXOP) of the second WTRU, and wherein the CF-End frame includes a duration field and a basic service set identifier (BSSID) field;

updating the first and second NAV counters based on the received CF-End frame; and

determining whether to attempt to access a medium based on the updated first and second NAV counter.

14. The method of claim 13 further comprising:

updating the first and second NAV counters of the first WTRU based on a value set in the duration field in the received CF-End frame.

15. The method of claim 13 further comprising:

updating the first and second NAV counters of the first WTRU based on the BSSID field in the received CF-End frame.

16. The method of claim 13 further comprising:

maintaining a TXOP holder MAC address for the BSS based on a transmitter address in a received frame from the TXOP holder.

17. The method of claim 13 further comprising:

maintaining a TXOP holder MAC address for the BSS based on a receiver address in a received frame from the TXOP holder.

18. The method of claim 13 further comprising:

maintaining a TXOP holder MAC address for the BSS based on the duration field in a received frame from the TXOP holder.