Elements of information theory
Elements of information theory
IEEE Transactions on Wireless Communications
Improving the rates in wireless relay systems through superposition coding
IEEE Transactions on Wireless Communications - Part 1
Comments on broadcast channels
IEEE Transactions on Information Theory
IEEE Transactions on Information Theory
A recursive algorithm for the exact BER computation of generalized hierarchical QAM constellations
IEEE Transactions on Information Theory
Cooperative diversity in wireless networks: Efficient protocols and outage behavior
IEEE Transactions on Information Theory
Cooperative communication in wireless networks
IEEE Communications Magazine
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Relay-assisted cooperative communications are a promising solution for error-performance improvement and cell coverage extension. However, additional resources such as time slots or frequency bands are required for the relay, which reduce the overall throughput. This paper proposes two cooperative relay schemes that employ hierarchical modulation to overcome this limitation. One scheme is for symmetric downlink communications and the other is for asymmetric downlink communications. These schemes exploit the hierarchical modulation symbols for users in the network and allow the system to transmit two or more independent data streams simultaneously. The proposed schemes reduce the number of transmission phases to the same as conventional schemes without diversity gain. The symbol-error rates of the proposed systems are a function of the distance parameter of hierarchical modulation. By flexibly controlling the distance parameter based on specific scenarios, it allows an extra degree of freedom to guarantee error performance of receivers whose signals undergo different losses.