Closed-loop architecture and protocols for rapid dynamic spreading gain adaptation in CDMA networks
IEEE/ACM Transactions on Networking (TON)
IEEE Transactions on Wireless Communications
On the throughput gain for rapid dynamic symbol duration adaptation within discrete duration sets
ISCIT'09 Proceedings of the 9th international conference on Communications and information technologies
Optimal multiplexed hierarchical modulation for unequal error protection of progressive bit streams
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Optimization of hierarchical modulation for use of scalable media
EURASIP Journal on Advances in Signal Processing
Maximizing throughput in cooperative networks via cross-layer adaptive designs
Sarnoff'10 Proceedings of the 33rd IEEE conference on Sarnoff
MILCOM'09 Proceedings of the 28th IEEE conference on Military communications
DNCOCO'06 Proceedings of the 5th WSEAS international conference on Data networks, communications and computers
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The characteristics of mobile wireless communication channels fluctuate for many reasons, including movement of the radios, changes in path attenuation, and variations in interference. Several adaptive signaling techniques have been proposed for use in wideband code-division multiple-access (CDMA) systems including adaptive data rates, adaptive spreading code rates, discontinuous transmission, and multicode CDMA. We introduce adaptive signaling techniques that use nonuniform phase-shift-key (PSK) modulation. These techniques have several advantages for use in CDMA communications, and they support multimedia transmission by simultaneously delivering different types of traffic, each with its own required quality of service. The signaling methods that we propose deliver a basic message at a specified error rate and simultaneously deliver an additional message by exploiting any extra capability that is available. We show that by adapting the location of the points in a PSK constellation, the throughput can be maximized for the additional message while maintaining an acceptable error rate for the basic message. Responses to larger changes in channel quality are accomplished by adapting the PSK constellation size, signaling rate, and error-correcting code. Examples of adaptive signaling schemes that employ nonuniform PSK constellations are presented, including an application to a cellular CDMA system