Capacity of Wireless Networks within o(log(SNR)) - the Impact of Relays, Feedback, Cooperation and Full-Duplex Operation

Abstract

Recent work has characterized the sum capacity of time-varying/frequency-selective wireless interference networks and $X$ networks within $o(\log (SNR))$, i.e., with an accuracy approaching 100% at high SNR (signal to noise power ratio). In this paper, we seek similar capacity characterizations for wireless networks with relays, feedback, full duplex operation, and transmitter/receiver cooperation through noisy channels. First, we consider a network with $S$ source nodes, $R$ relay nodes and $D$ destination nodes with random time-varying/frequency-selective channel coefficients and global channel knowledge at all nodes. We allow full-duplex operation at all nodes, as well as causal noise-free feedback of all received signals to all source and relay nodes. The sum capacity of this network is characterized as $\frac{SD}{S+D-1}\log (SNR)+o(\log (SNR))$. The implication of the result is that the capacity benefits of relays, causal feedback, transmitter/receiver cooperation through physical channels and full duplex operation become a negligible fraction of the network capacity at high SNR. Some exceptions to this result are also pointed out in the paper. Second, we consider a network with $K$ full duplex nodes with an independent message from every node to every other node in the network. We find that the sum capacity of this network is bounded below by $\frac{K(K-1)}{2K-2}+o(\log (SNR))$ and bounded above by $\frac{K(K-1)}{2K-3}+o(\log (SNR))$.

References in corpus (7)

• A Deterministic Approach to Wireless Relay Networks
• Degrees of Freedom Region for the MIMO X Channel
• On Cognitive Interference Networks
• Interference Alignment on the Deterministic Channel and Application to Fully Connected AWGN Interference Networks
• Degrees of Freedom of Wireless X Networks
• Gaussian Interference Channel Capacity to Within One Bit
• The Multiplexing Gain of MIMO X-Channels with Partial Transmit Side-Information

Cited by in corpus (2)

• On the Capacity and Generalized Degrees of Freedom of the X Channel
• Degrees of Freedom of the MIMO Interference Channel with Cooperation and Cognition