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On Ergodic Sum Capacity of Fading Cognitive Multiple-Access and Broadcast Channels (2009)
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BibTeX
@MISC{Zhang09onergodic,
author = {Rui Zhang and Shuguang Cui and Ying-chang Liang},
title = { On Ergodic Sum Capacity of Fading Cognitive Multiple-Access and Broadcast Channels},
year = {2009}
}
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Abstract
This paper studies the information-theoretic limits of a secondary or cognitive radio (CR) network under spectrum sharing with an existing primary radio network. In particular, the fading cognitive multiple-access channel (C-MAC) is first studied, where multiple secondary users transmit to the secondary base station (BS) under both individual transmit-power constraints and a set of interference-power constraints each applied at one of the primary receivers. This paper considers the long-term (LT) or the short-term (ST) transmit-power constraint over the fading states at each secondary transmitter, combined with the LT or ST interference-power constraint at each primary receiver. In each case, the optimal power allocation scheme is derived for the secondary users to achieve the ergodic sum capacity of the fading C-MAC, as well as the conditions for the optimality of the dynamic time-division-multiple-access (D-TDMA) scheme in the secondary network. The fading cognitive broadcast channel (C-BC) that models the downlink transmission in the secondary network is then studied under the LT/ST transmit-power constraint at the secondary BS jointly with the LT/ST interference-power constraint at each of the primary receivers. It is shown that D-TDMA is indeed optimal for achieving the ergodic sum capacity of the fading C-BC for all combinations of transmit-power and interference-power constraints.
Keyphrases
ergodic sum capacity fading cognitive multiple-access primary receiver broadcast channel secondary network cognitive radio interference-power constraint convex optimization primary radio network multiple-access channel secondary base station secondary b individual transmit-power constraint fading c-bc information-theoretic limit multiple secondary user fading c-mac st interference-power constraint spectrum sharing lt st interference-power constraint downlink transmission index term broadcast channel secondary transmitter paper study fading state fading cognitive multiple-access channel secondary user optimal power allocation scheme lt st transmit-power constraint fading cognitive broadcast channel ergodic capacity transmit-power constraint interference temperature dynamic resource allocation
