Title :
Interference alignment and neutralization in a cognitive 3-user MAC-interference channel: degrees of freedom
Author :
Chaaban, Anas ; Sezgin, Aydin
Author_Institution :
Emmy-Noether Res. Group on Wireless Networks, Ulm Univ., Ulm, Germany
Abstract :
A network consisting of a point-to-point (P2P) link and a multiple access channel (MAC) sharing the same medium is considered. The resulting interference network, with three transmitters and two receivers is studied from degrees of freedom (DoF) perspective, with and without cognition. Several cognition variants are examined. Namely, the setup is studied with (1) no cognitive transmitters, (2) a cognitive P2P transmitter, (3) one cognitive MAC transmitter, and (4) with two cognitive MAC transmitters. It is shown that having a cognitive P2P transmitter does not bring any DoF gain to the network. This is obtained by showing that the DoF of the two former cases (1) and (2) is 1. However, it is shown that a cognitive MAC transmitter is more beneficial since the latter two cases (3) and (4) have 3/2 DoF. The achievability of 3/2 DoF is guaranteed by using a combination of interference neutralization and interference alignment.
Keywords :
access protocols; cognitive radio; multi-access systems; peer-to-peer computing; radio links; radio receivers; radio transmitters; radiofrequency interference; wireless channels; DoF gain; P2P link; cognitive 3-user MAC-interference channel; cognitive MAC transmitter; cognitive P2P transmitter; degrees of freedom; interference alignment; interference network; interference neutralization; multiple access channel; point-to-point link; receiver; Cognition; Cognitive radio; Interference; Radio transmitters; Receivers; Upper bound;
Conference_Titel :
Information Theory (CWIT), 2011 12th Canadian Workshop on
Conference_Location :
Kelowna, BC
Print_ISBN :
978-1-4577-0743-8
DOI :
10.1109/CWIT.2011.5872116
