Abstract
We investigate the resource allocation problem for an OFDM cooperative network with a single source-destination pair and multiple relays. Assuming knowledge of the instantaneous channel gains for all links in the entire network, we propose several bit and power allocation schemes aiming at minimizing the total transmission power under a target rate constraint. First, an optimal and efficient bit loading algorithm is proposed when the relay node uses the same subchannel to relay the information transmitted by the source node. To further improve the performance gain, subchannel permutation, in which the subchannels are reallocated at relay nodes, is considered. An optimal subchannel permutation algorithm is first proposed and then an efficient suboptimal algorithm is considered to achieve a better complexity-performance tradeoff. A distributed bit loading algorithm is also proposed for ad hoc networks. Simulation results show that significant performance gains can be achieved by the proposed bit loading algorithms, especially when subchannel permutation is employed.
Highlights
In cooperative systems, a group of single-antenna nodes transmits as a “virtual antenna array,” obtaining diversity gain without requiring multiple antennas at individual nodes
We employ subchannel permutation, in which the subchannels are reallocated at relay nodes, and devise bit loading algorithms for cooperative Orthogonal frequency-division multiplexing (OFDM) systems with decode-and-forward relaying strategy
We present simulation results to compare the performance of the different bit loading algorithms
Summary
A group of single-antenna nodes transmits as a “virtual antenna array,” obtaining diversity gain without requiring multiple antennas at individual nodes. Much recent work has addressed aspects of cooperative diversity, and significant benefits can be achieved (e.g., see [1, 2]). The use of orthogonal signaling and the inherent frequency diversity in a well-designed OFDM system are especially useful in obtaining the maximum benefits from cooperation. Relay and cooperative networks with OFDM(A) transceivers have been proposed for applications in several emerging systems. IEEE 802.16’s Relay Task Group [5] is a developing standard for 802.16-based multihop networks. Relaying is considered in IEEE 802.11s [6], a developing mesh networking standard
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: EURASIP Journal on Wireless Communications and Networking
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
