Paper Info
Title
Degrees of Freedom for a MIMO Gaussian -Way Relay Channel: Successive Network Code Encoding and Decoding
Abstract
This paper studies a network information flow problem for a multiple-input multiple-output (MIMO) Gaussian wireless network with $K$ users and a single intermediate relay having $M$ antennas. In this network, each user sends a multicast message to all other users while receiving $K-1$ independent messages from the other users via an intermediate relay. This network information flow is termed a MIMO Gaussian $K$-way relay channel. For this channel, it is shown that the optimal sum degrees of freedom (sum-DoF) is ${KM}/{K-1}$, assuming that all nodes have global channel knowledge and operate in full-duplex. A converse argument is derived by cut-set bounds. The achievability is shown by a repetition coding scheme with random beamforming in encoding and a zero-forcing method combined with self-interference cancelation in decoding. Furthermore, under the premise that all nodes have local channel state information at the receiver only and operate in half-duplex mode, it is shown that a total ${K}/{2}$ DoF is achievable when $M=K-1$. The key to showing this result is a novel encoding and decoding scheme, which creates a set of network code messages with a chain structure during the multiple access phase and performs successive interference cancelation using side-information for the broadcast phase. One major implication of the derived results is that efficient exploitation of the transmit message as side-information leads to an increase in the sum-DoF gain in a multiway relay channel with multicast messages.
Year
DOI
Venue
2014
10.1109/TIT.2014.2298138
Information Theory, IEEE Transactions  
Keywords
Field
DocType
Gaussian channels,MIMO communication,antennas,array signal processing,decoding,encoding,multicast communication,Gaussian k-way relay channel,K-1 independent messages,M antennas,MIMO,decoding,multicast message,multiple-input multiple-output,multiway relay channel,network information flow,optimal sum degrees of freedom,successive network code encoding,Degrees of freedom,multi-way relay channels,network coding
Linear network coding,Discrete mathematics,Topology,Wireless network,Relay channel,Computer science,MIMO,Multicast,Decoding methods,Relay,Channel state information,Distributed computing
Journal
Volume
Issue
ISSN
60
3
0018-9448
Citations 
PageRank 
References 
7
0.45
17
Authors
2
Name
Order
Citations
PageRank
Namyoon Lee185762.30
Joohwan Chun239635.12