Title
Message Passing in C-RAN: Joint User Activity and Signal Detection.
Abstract
In cloud radio access network (C-RAN), remote radio heads (RRHs) and users are uniformly distributed in a large area such that the channel matrix can be considered as sparse. Based on this phenomenon, RRHs only need to detect the relatively strong signals from nearby users and ignore the weak signals from far users, which is helpful to develop low-complexity detection algorithms without causing much performance loss. However, before detection, RRHs require to obtain the real-time user activity information by the dynamic grant procedure, which causes the enormous latency. To address this issue, in this paper, we consider a grant-free C-RAN system and propose a low-complexity Bernoulli-Gaussian message passing (BGMP) algorithm based on the sparsified channel, which jointly detects the user activity and signal. Since active users are assumed to transmit Gaussian signals at any time, the user activity can be regarded as a Bernoulli variable and the signals from all users obey a Bernoulli-Gaussian distribution. In the BGMP, the detection functions for signals are designed with respect to the Bernoulli-Gaussian variable. Numerical results demonstrate the robustness and effectivity of the BGMP. That is, for different sparsified channels, the BGMP can approach the mean-square error (MSE) of the genie-aided sparse minimum mean-square error (GA-SMMSE) which exactly knows the user activity information. Meanwhile, the fast convergence and strong recovery capability for user activity of the BGMP are also verified.
Year
DOI
Venue
2017
10.1109/glocom.2017.8254230
IEEE Global Communications Conference
Keywords
DocType
Volume
C-RAN,Bernoulli-Gaussian,message passing,user activity and signal detection
Conference
abs/1708.05939
ISSN
Citations 
PageRank 
2334-0983
2
0.35
References 
Authors
6
6
Name
Order
Citations
PageRank
Yuhao Chi1294.74
Lei Liu258864.83
Guanghui Song37913.90
Chau Yuen44493263.28
Yong Liang Guan52037163.66
Ying Li6505.51