On the Capacity Enlargement of Gaussian Broadcast Channels with Passive Noisy Feedback

09/18/2020
by   Aditya Narayan Ravi, et al.
0

It is well known that the capacity region of an average transmit power constrained Gaussian Broadcast Channel (GBC) with independent noise realizations at the receivers is enlarged by the presence of causal noiseless feedback. Capacity region enlargement is also known to be possible by using only passive noisy feedback, when the GBC has identical noise variances at the receivers. The last fact remains true even when the feedback noise variance is very high, and available only from one of the receivers. While such capacity enlargements are feasible for several other feedback models in the Gaussian BC setting, it is also known that feedback does not change the capacity region for physically degraded broadcast channels. In this paper, we consider a two user GBC with independent noise realizations at the receivers, where the feedback links from the receivers are corrupted by independent additive Gaussian noise processes. We investigate the set of four noise variances, two forward and two feedback, for which no capacity enlargement is possible. A sharp characterization of this region is derived, i.e., any quadruple outside the presented region will lead to a capacity enlargement, whereas quadruples inside will leave the capacity region unchanged. Our results lead to the conclusion that when the forward noise variances are different, too noisy a feedback from one of the receivers alone is not always beneficial for enlarging the capacity region, be it from the stronger user or the weaker one, in sharp contrast to the case of equal forward noise variances.

READ FULL TEXT
POST COMMENT

Comments

There are no comments yet.

Authors

page 1

page 2

page 3

page 4

10/14/2019

Capacity Region of Erasure Broadcast Channels with Common Message and Feedback

Jolfaei et al. used feedback to create transmit signals that are simulta...
01/20/2018

Secrecy Capacity of Colored Gaussian Noise Channels with Feedback

In this paper, the k-th order autoregressive moving average (ARMA(k)) Ga...
07/10/2018

Parallel Gaussian Channels Corrupted by Independent States With a State-Cognitive Helper

We consider a state-dependent parallel Gaussian channel with independent...
05/04/2021

Effects of Quantization on the Multiple-Round Secret-Key Capacity

We consider the strong secret key (SK) agreement problem for the satelli...
03/05/2013

Impulsive Noise Mitigation in Powerline Communications Using Sparse Bayesian Learning

Additive asynchronous and cyclostationary impulsive noise limits communi...
01/17/2018

Mixed Delay Constraints in Wyner's Soft-Handoff Network

Wyner's soft-handoff network with mixed delay constraints is considered ...
This week in AI

Get the week's most popular data science and artificial intelligence research sent straight to your inbox every Saturday.