Method for controlling medium access in full-duplex Wi-Fi network

Patent metadata

Field	Value
Publication number	US-10057042-B2
Application number	US-201615065804-A
Country	US
Kind code	B2
Filing date	Mar 9, 2016
Priority date	Mar 20, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

The present invention includes: defining a transmission signal generated by the AP and a transmitter (TX) configured to transmit a signal to the AP and reception signals generated by the AP and receivers (RXs) configured to receive a signal from the AP, and canceling self-interference in consideration of a channel gain of the self-interference at the AP; defining a channel transmitted from the TX to the AP as uplink, defining a channel transmitted from the AP to the RX as downlink, and deriving a signal-to-interference-plus-noise ratio (SINR) for a signal transmittable on the uplink and the downlink; selecting an RX capable of maximizing a capacity sum of transmit powers of the AP and the TX; and selecting optimum transmit powers of the AP and the TX for maximizing SINRs of transmission on the uplink and the downlink.

First claim

What is claimed is:

1. A method for controlling medium access in a full-duplex Wi-Fi network, the method comprising:
transmitting a Clear To Send-Uplink (CTS-U) frame to a transmitter (TX) and receiver (RX) candidates upon receiving a Request To Send (RTS) frame from the TX;
receiving a Clear To Send-Downlink (CTS-D) frame from a RX that won a contention among the RX candidates;
calculating an optimum transit power of an access point (AP) and an optimum transit power of the TX using the CTS-D;
transmitting an AP Header (HA) frame including the optimum transit power of the TX at the optimum transit power of the AP;
canceling self-interference to receive an uplink data frame from the TX;
receiving the uplink data frame transmitted from the TX at the optimum transit power of the TX; and
transmitting a downlink data frame to the RX that won a contention.

2. The method according to claim 1 , wherein the canceling self-interference to receive an uplink data frame from the TX comprises:
canceling self-interference by compensating the channel gain at the AP.

3. The method according to claim 1 , wherein the calculating an optimum transit power of an AP and an optimum transit power of the TX using the CTS-D comprises:
deriving signal-to-interference-plus-noise ratios (SINRs) of the RX and the AP in consideration of transmit powers of clients;
deriving a threshold of the SINRs for transmission from the AP to the RX and from the TX to the AP; and
deriving, by the AP, a transmission sum rate of the uplink and the downlink.

4. The method according to claim 3 , wherein the deriving of the SINRs of the RX and the AP comprises:
defining power (P r,i→j ) received by a j-th client according to a signal transmitted from an i-th client and self-interference power (P r,SI ) at the AP; and
defining transmit power (P t,i ) of the i-th client,
wherein the transmit power (P t,i ) is expressed as the following equation:
P r,i→j =|G i,j | 2 ·E (| X i | 2 )=| G i,j | 2 ·P t,i ,
P r,SI =|G i,j | 2 ·E (| X AP | 2 )=| G AP,AP | 2 ·P t,AP ,  [Equation].

5. The method according to claim 3 , wherein the transmission sum rate is derived from the following equation:
sum =log 2 (1+SINR Uplink )+log 2 (1+SINR Downlink ),(bits/s/Hz)  [Equation].

6. The method according to claim 1 , wherein the RX that won a contention is determined based on Received Signal Strength Based (RSSB) contention mechanism among the RX candidates.

7. The method according to claim 1 , wherein the optimum transit power of an AP and the optimum transit power of the TX are determined in consideration of power information received from the TX and the RX that won a contention, inter-client interference information, and information on self-interference at the AP.

8. The method according to claim 1 , further comprising:
deriving a minimum SINR for transmission on the uplink and the downlink,
wherein the minimum SINR is set to be greater than a SINR threshold γ for transmission from the AP to the RX and from the TX to the AP and is expressed as the following equation:

SINR
Uplink

=



G

TX
,
AP



2

·

P

t
,
TX



G

AP
,
AP



2

α

·

P

t
,
AP

+

N
AP

≥
γ

,

⁢

SINR
Downlink

=



G

AP
,
RX



2

·

P

t
,
AP



G

TX
,
RX



2

·

P

t
,
TX

Assignees

• Gwangju Inst Science & Tech

Inventors

• Lim Hyuk
• Choi Wooyeol

Classifications

• H04L5/14

  Two-way operation using the same type of signal, i.e. duplex · CPC title

• H04W28/12

  using signalling between network elements · CPC title

• H04L1/00

  Arrangements for detecting or preventing errors in the information received {(correcting synchronisation H04L7/00)} · CPC title

• H04L5/0055

  Physical resource allocation for ACK/NACK (for physical mapping arrangements in ARQ protocols H04L1/1861) · CPC title

• H04L5/006 Primary

  Quality of the received signal, e.g. BER, SNR, water filling · CPC title