Multiple-input multiple-output wireless communications with full duplex radios

• US 9,137,788 B2
• Filed: 08/17/2012
• Issued: 09/15/2015
• Est. Priority Date: 09/05/2011
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Laboratories America Inc (NEC Corporation)
• Inventors: Khojastepour, Mohammad A., Barghi, Sanaz, Sundaresan, Karthikeyan, Rangarajan, Sampath
• Primary Examiner(s): Banks Harold, Marsha D
• Assistant Examiner(s): JOHNSON, WILLIAM D
• Application Number:
  US13/588,466
• Publication Number:
  US 20130155912A1
• Time in Patent Office: 1,124 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04L 5/0025 Spatial division following the spatial signature of the channel
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

An apparatus used in a full duplex multiple-input multiple-output (MIMO) wireless communications system is disclosed. In an aspect, the apparatus includes a plurality of antennas, each of which is connected to a combination of at least a TX (transmit) RF (radio frequency) chain and an RX (receive) RF chain. The plurality of antennas are split into one or more transmit antennas and one or more receive antennas, and the apparatus communicates with another apparatus. Other apparatuses and some methods for wireless communications also are disclosed.

Claims

1. An apparatus used in a single-channel full duplex multiple-input multiple-output (MIMO) wireless communications system, the apparatus comprising:

a plurality of antennas, each of which is connected to a combination of at least a TX (transmit) RF (radio frequency) chain and an RX (receive) RF chain,

wherein the plurality of antennas are split into one or more transmit antennas and one or more receive antennas,

wherein the apparatus communicates with another apparatus,

wherein the antenna splitting is performed so that capacity gain is maximized, and

wherein the capacity gain is given by the following formula;

2. The apparatus as in claim 1,

wherein the antenna splitting is based on a channel condition.

3. The apparatus as in claim 1,

wherein, in case that an SNR (signal to noise ratio) is less than a predetermined value, N₁ and M₁ are set to one, where M₁ and N₁ are the numbers of transmit antennas at the apparatus and said another apparatus, respectively.

4. The apparatus as in claim 1,

wherein, in case that an SNR (signal to noise ratio) is more than a predetermined value, M₁ is set to M/2 (when M is even) or M/2±

½

(when M is odd) and N₁ is set to N/2 (when N is even) or N/2±

½

(when N is odd), where M and N are the numbers of antennas at the apparatus and said another apparatus, respectively, and M₁ and N₁ are the numbers of transmit antennas at the apparatus and said another apparatus, respectively.

5. The apparatus as in claim 1,

wherein, in case that an SNR (signal to noise ratio) is more than a predetermined value, M₁ is set to a value so that the following inequality is satisfied:

M>

M₁+N₁>

N,

where M and N are the numbers of antennas at the apparatus and said another apparatus, respectively, and M₁ and N₁ are the numbers of transmit antennas at the apparatus and said another apparatus, respectively.

6. A method implemented in a base station used in a single-channel full duplex multiple-input multiple-output (MIMO) wireless communications system, the method comprising:

scheduling one or more user equipment in an OFDM (Orthogonal Frequency Division Multiplexing) tone used for single-channel full duplex communications, according to a prior schedule and an achieved rate,

wherein the achieved rate comprises a weighted sum rate, and

wherein the weighted sum rate can be expressed as the following expression;

7. The method as in claim 6, wherein a weight for the weighted sum rate changes in time according to at least one of operation of the single-channel full duplex MIMO wireless communications system and a channel condition.