System and method for interference protection in downlink multi-user multiple-input, multiple-output communication

• US 8,837,478 B1
• Filed: 07/22/2011
• Issued: 09/16/2014
• Est. Priority Date: 07/23/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Nemavat, Pradeep Jugraj, Goel, Sandesh
• Primary Examiner(s): Chriss, Andrew
• Assistant Examiner(s): FAYED, RASHA K
• Application Number:
  US13/189,087
• Time in Patent Office: 1,152 Days
• Field of Search: 370/254, 370/255, 370/328, 370/329, 370/338, 370/390, 370/432
• US Class Current: 370/390
• CPC Class Codes: H04L 12/1868 Measures taken after transmission, e.g. acknowledgments
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 45/34 Source routing
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

An access point includes a packet generation module, a packet detection module, and a downlink control module. The packet generation module is configured to generate a multi-user request-to-send (MU-RTS) packet for transmission to each of N remote nodes, wherein N is an integer greater than one. The packet detection module is configured to detect clear-to-send (CTS) packets received from ones of the N remote nodes. The downlink control module is configured to control a downlink to M of the N remote nodes after M CTS packets are detected, wherein M is based on the MU-RTS packet, and wherein M is an integer less than or equal to N.

Claims

1. An access point comprising:

a packet generation module configured to generate a multi-user request-to-send packet for transmission to each of N remote nodes,

wherein

the multi-user request-to-send packet includes a plurality of addresses,

each of the plurality of addresses is for a respective one of M of the N remote nodes,

N is an integer greater than one, and

M is an integer (i) less than or equal to N, and (ii) greater than or equal to 1;

a packet detection module configured to detect clear-to-send packets received from ones of the N remote nodes; and

a downlink control module configured to, based on the plurality of addresses, control a downlink to the M of the N remote nodes after M clear-to-send packets are detected respectively from the M of the N remote nodes,

wherein

a transmission of a first one of the clear-to-send packets begins a short interframe space period after receiving the multi-user request-to-send packet,

transmissions of a remainder of the clear-to-send packets are sequential, and

start times of each of the transmissions of the remainder of the clear-to-send packets is based on

a transmission end time of the multi-user request-to-send packet,

the short interframe space period, and

a product of (i) a number of previously transmitted clear-to-send packets, and (ii) a sum of an amount of time to transmit one of the clear-to-send packets and the short interframe space period.

2. The access point of claim 1, wherein the multi-user request-to-send packet has a variable length.

3. The access point of claim 2, wherein the variable length is based on M.

4. The access point of claim 1, wherein the multi-user request-to-send packet has a predetermined length.

5. The access point of claim 4, wherein the predetermined length is based on N.

6. The access point of claim 1, wherein N equals four.

7. The access point of claim 1, wherein each of the transmissions of the remainder of the clear-to-send packets are separated by a sum of the short interframe space period and a transmission time for a clear-to-send packet.

8. The access point of claim 1, wherein:

the multi-user request-to-send packet includes a duration field; and

the duration field is used to set a network allocation vector for N-M of the N remote nodes.

10. The access point of claim 1, wherein the downlink control module is configured to initiate transmission of data packets to the M of the N remote nodes, respectively, the short interframe space after the M clear-to-send packets are detected.

11. The access point of claim 1, wherein:

in response to receiving X clear-to-send packets instead of M clear-to-send packets, the downlink control module is configured to initiate transmission of data packets to X of the N remote nodes instead of initiating transmission of data packets to the M of the N remote nodes;

the downlink control module is configured to transmit the data packets to the X of the N remote nodes a predetermined period after the multi-user request-to-send packet was received;

X is a number of clear-to-send packets received during the predetermined period; and

X is an integer greater than zero and less than M.

12. The access point of claim 10, wherein each of the M of the N remote nodes transmits an acknowledgement packet after receiving a data packet.

13. The access point of claim 12, wherein:

the downlink control module is configured to initiate transmission of a contention free end packet to each of the N remote nodes after the M acknowledgement packets are received; and

the contention free end packet resets a network allocation vector for each of the N remote nodes.

14. The access point of claim 13, wherein the downlink control module is configured to initiate transmission of the contention free end packet when zero clear-to-send packets have been received within a predetermined period after the multi-user request-to-send packet was received.

15. The access point of claim 13, wherein the downlink control module is configured to initiate transmission of the contention free end packet when greater than zero clear-to-send packets and less than M clear-to-send packets have been received within a predetermined period.

24. The access point of claim 1, wherein:

the clear-to-send packets are received at respective time periods and in an order in which the corresponding plurality of addresses were included in the multi-user request-to-send packet; and

consecutive ones of the time periods are separated by respective short interframe space periods.

9. An access point comprising:

a packet generation module configured to generate a multi-user request-to-send packet for transmission to each of N remote nodes,

wherein

the multi-user request-to-send packet includes a plurality of addresses,

each of the plurality of addresses is for a respective one of M of the N remote nodes,

N is an integer greater than one, and

M is an integer (i) less than or equal to N, and (ii) greater than or equal to 1;

a packet detection module configured to detect clear-to-send packets received from ones of the N remote nodes; and

a downlink control module configured to, based on the plurality of addresses, control a downlink to the M of the N remote nodes after M clear-to-send packets are detected respectively from the M of the N remote nodes,

wherein

the multi-user request-to-send packet includes a duration field,

the duration field is used to set a network allocation vector for N-M of the N remote nodes,

the N remote nodes ignore network allocation vector information in the clear-to-send packets transmitted from the M of the N remote nodes for a predetermined period,

the clear-to-send packets are sent by the M of the N nodes during the predetermined period

a transmission of a first one of the clear-to-send packets begins a short interframe space period after receiving the multi-user request-to-send packet,

transmissions of a remainder of the clear-to-send packets are sequential, and

start times of each of the transmissions of the remainder of the clear-to-send packets is based on

a transmission end time of the multi-user request-to-send packet,

the short interframe space period, and

a product of (i) a number of previously transmitted clear-to-send packets, and (ii) a sum of an amount of time to transmit one of the clear-to-send packets and the short interframe space period.

25. The access point of claim 9, wherein a length of the predetermined period is based on an amount of time for each of the N remote nodes to send a respective clear-to-send packet.

16. A method comprising:

generating a multi-user request-to-send packet for transmission to each of N remote nodes,

wherein

the multi-user request-to-send packet includes a plurality of addresses,

each of the plurality of addresses is for a respective one of M of the N remote nodes,

N is an integer greater than one, and

M is an integer (i) less than or equal to N, and (ii) greater than or equal to 1;

detecting clear-to-send packets received from ones of the N remote nodes; and

based on the plurality of addresses, controlling a downlink to the M of the N remote nodes after M clear-to-send packets are detected respectively from the M of the N remote nodes,

wherein

a transmission of a first one of the clear-to-send packets begins a short interframe space period after receiving the multi-user request-to-send packet,

transmissions of a remainder of the clear-to-send packets are sequential, and

start times of each of the transmissions of the remainder of the clear-to-send packets is based on

a transmission end time of the multi-user request-to-send packet,

the short interframe space period, and

a product of (i) a number of previously transmitted clear-to-send packets, and (ii) a sum of an amount of time to transmit one of the clear-to-send packets and the short interframe space period.

17. The method of claim 16, wherein the multi-user request-to-send packet has a variable length.

18. The method of claim 17, wherein the variable length is based on M.

19. The method of claim 16, wherein the multi-user request-to-send packet has a predetermined length.

20. The method of claim 19, wherein the predetermined length is based on N.

21. The method of claim 19, wherein N equals four.

22. The method of claim 16, wherein each of the transmissions of the remainder of the clear-to-send packets are separated by a sum of the short interframe space period and a transmission time for a clear-to-send packet.

23. The method of claim 16, wherein:

the multi-user request-to-send packet includes a duration field; and

the duration field is used to set a network allocation vector for N-M of the N remote nodes.