Title :
Can feedback, cooperation, relays and full duplex operation increase the degrees of freedom of wireless networks?
Author :
Cadambe, Viveck R. ; Jafar, Syed A.
Author_Institution :
Electr. Eng. & Comput. Sci., Univ. of California Irvine, Irvine, CA
Abstract :
We consider a fully connected network with S full duplex source nodes, D full duplex destination nodes and R relay nodes, perfect feedback to source and relay nodes, and noisy cooperation between all source, relay and destination nodes. We show that this network has SD/S+D-1 degrees of freedom if the channel gains are time-varying/frequency selective. The implication of the result is that, the techniques mentioned in the title (i.e relays etc.) can affect the capacity of a network only up to a o(log(SNR)) term and therefore cannot improve the degrees of freedom of a network. Certain communication scenarios excluded by our system model where these techniques improve the degrees of freedom are also identified. Bounds on the degrees of freedom of a fully connected K node network emerge as a by-product of our study.
Keywords :
channel capacity; radio networks; time-varying channels; D-full duplex destination nodes; R-relay nodes; S-full duplex source nodes; channel gains; degrees of freedom; time-varying-frequency selective; wireless networks; Computer science; Feedback; Frequency; Interference; Relays; Signal to noise ratio; Spread spectrum communication; Wireless networks;
Conference_Titel :
Information Theory, 2008. ISIT 2008. IEEE International Symposium on
Conference_Location :
Toronto, ON
Print_ISBN :
978-1-4244-2256-2
Electronic_ISBN :
978-1-4244-2257-9
DOI :
10.1109/ISIT.2008.4595190