scholarly journals An achievable region for the Wiretap multiple-access channel with common message

2012 ◽  
Author(s):  
Moritz Wiese ◽  
Holger Boche
Keyword(s):  
Multiple Access ◽  
Multiple Access Channel ◽  
Access Channel ◽  
Achievable Region ◽  
Common Message

scholarly journals A Capacity-Achieving Feedback Scheme of the Gaussian Multiple-Access Channel with Degraded Message Sets

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 756
Author(s):  
Haoheng Yuan ◽  
Bin Dai
Keyword(s):  
Multiple Access ◽  
Multiple Access Channel ◽  
Gaussian Channel ◽  
Capacity Region ◽  
Access Channel ◽  
Feedback Scheme ◽  
Point To Point ◽  
Noiseless Feedback ◽  
Common Message ◽  
Type Feedback

The classical Schalkwijk–Kailath (SK) scheme for the point-to-point white Gaussian channel with noiseless feedback plays an important role in information theory due to the fact that it is capacity-achieving and the complexity of its encoding–decoding procedure is extremely low. In recent years, it has been shown that an extended SK feedback scheme also achieves the capacity region of the two-user Gaussian multiple-access channel with noiseless feedback (GMAC-NF), where two independent messages are, respectively, encoded by two intended transmitters. However, for the two-user GMAC-NF with degraded message sets (one common message for both users and one private message for an intended user), the capacity-achieving feedback scheme remains open. In this paper, we propose a novel two-step SK-type feedback scheme for the two-user GMAC-NF with degraded message sets and show that this scheme is capacity-achieving.

scholarly journals On the Downlink Capacity of Cell-Free Massive MIMO with Constrained Fronthaul Capacity

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 418
Author(s):  
Peng Zhang ◽  
Frans M. J. Willems
Keyword(s):  
Multiple Access ◽  
Linear Growth ◽  
Multiple Access Channel ◽  
Access Channel ◽  
A Cell ◽  
Downlink Capacity ◽  
Constrained Capacity ◽  
Common Message ◽  
Single Receiver ◽  
Logarithmic Growth

We investigate the downlink of a cell-free massive multiple-in multiple-out system in which all access points (APs) are connected in a linear-topolpgy fronthaul with constrained capacity and send a common message to a single receiver. By modeling the system as an extension of the multiple-access channel with partially cooperating encoders, we derive the channel capacity of the two-AP setting and then extend the results to arbitrary N-AP scenarios. By developing a cooperating mode concept, we investigate the optimal cooperation among the encoders (APs) when we limit the total fronthaul capacity, and the total transmit power is constrained as well. It is demonstrated that achieving capacity requires a water-pouring distribution of the total available fronthaul capacity over the fronthaul links. Our study reveals that a linear growth of total fronthaul capacity results in a logarithmic growth of the beamforming capacity. Moreover, even if the number of APs would be unlimited, only a finite number of them need to be activated. We found an expression for this number.

scholarly journals Multiple access channel with common message and secrecy constraint

2016 ◽  
Vol 10 (1) ◽  
pp. 98-110 ◽  
Author(s):  
Hassan Zivari-Fard ◽  
Bahareh Akhbari ◽  
Mahmoud Ahmadian-Attari ◽  
Mohammad Reza Aref
Keyword(s):  
Multiple Access ◽  
Multiple Access Channel ◽  
Access Channel ◽  
Common Message
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