Degrees of Freedom of the MIMO Y Channel: Signal Space Alignment for Network Coding

Author

Lee, Namyoon ; Lim, Jong-Bu ; Chun, Joohwan

Author_Institution

Samsung Adv. Inst. of Technol. (SAIT), Samsung Electron. Co., Ltd., Yongin, South Korea

Volume

56

Issue

7

fYear

2010

fDate

7/1/2010 12:00:00 AM

Firstpage

3332

Lastpage

3342

Abstract

In this paper, we study a network information flow problem for a multiple-input-multiple-output (MIMO) Gaussian wireless network with three users each equipped with M antennas and a single intermediate relay equipped with N antennas. In this network, each user intends to convey independent messages for two different users via the intermediate relay while receiving two independent messages from the other two users. This is a generalized version of the two-way relay channel for the three-user case. We will call it a "MIMO Y channel." For this MIMO Y channel, we show that the capacity is 3M log(SNR) + o(log(SNR)) if N ≥ ⌈3M/2⌉ by using two novel signaling techniques, which are signal space alignment for network coding, and network-coding-aware interference nulling beamforming.

Keywords

MIMO communication; antenna arrays; computational complexity; network coding; radio networks; radiofrequency interference; wireless channels; MIMO Y channel; degrees of freedom; multiple-input-multiple-output Gaussian wireless network; network information flow problem; network-coding-aware interference nulling beamforming; signal space alignment; Array signal processing; Frequency; Information theory; Interference channels; MIMO; Network coding; Radio broadcasting; Relays; Wireless communication; Wireless networks; Degrees of freedom; interference alignment; multiple-input–multiple-output (MIMO) Y channel; network coding;

fLanguage

English

Journal_Title

Information Theory, IEEE Transactions on

Publisher

ieee

ISSN

0018-9448

Type

jour

DOI

10.1109/TIT.2010.2048486

Filename

5484988