A soft-decision scaling metric employing receiver statistics for direct-sequence spread-spectrum packet radio networks

Boyd, Steven W.; Pursley, M.B.; Royster, Thomas C.; Russell, H.B.

doi:10.1109/milcom.2008.4753233

Cited by 9 publications

(9 citation statements)

References 7 publications

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“…We compare the performance of our adaptive scaling metric with an adaptive LLR metric that requires channel measurements and with a fixed (nonadaptive) soft-decision metric. For channels with time-varying propagation loss or multiple-access interference, we show in [BPR08] that our adaptive scaling metric, which requires no channel measurements, gives approximately the same performance as the more complex LLR metric and better performance than fixed metrics. DS-SS modulation is also examined in [BoP09] for dynamic spectrum access networks in which initial power adjustments are required at the start of each session and adaptation to time-varying propagation conditions is required throughout the session.…”

Section: Scientific Progressmentioning

confidence: 87%

“…In [BPR08], [BoP09], and [BPR11], we investigated direct-sequence spread-spectrum (DS-SS) modulation formats, which are among the most robust formats for tactical cognitive radio networks. DS-SS modulation with adaptive soft-decision decoding is examined in [BPR08], where we derive a new metric from post-detection signal quality statistics that are developed in the demodulator of the tactical radio.…”

Section: Scientific Progressmentioning

confidence: 99%

“…DS-SS modulation with adaptive soft-decision decoding is examined in [BPR08], where we derive a new metric from post-detection signal quality statistics that are developed in the demodulator of the tactical radio. The metric is used to scale to the demodulator's soft-decision outputs before they are sent to the decoder.…”

Section: Scientific Progressmentioning

confidence: 99%

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Cognitive Radio for Tactical Wireless Communication Networks

Pursley¹

2011

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Research has been completed on adaptive modulation and coding for multicast transmission in a tactical packet radio network. Our adaptive multicast transmission compensates for changes in propagation conditions that occur from packet to packet during a session with one sender and multiple receivers. We also completed our research investigation of adaptive coding for frequency-hop communications over tactical communications channels that have time-varying fading and partial-band interference. New protocols were developed that combat fading and ABSTRACTResearch has been completed on adaptive modulation and coding for multicast transmission in a tactical packet radio network. Our adaptive multicast transmission compensates for changes in propagation conditions that occur from packet to packet during a session with one sender and multiple receivers. We also completed our research investigation of adaptive coding for frequency-hop communications over tactical communications channels that have time-varying fading and partial-band interference. New protocols were developed that combat fading and interference while providing throughput levels that are near the theoretical upper bounds. New distributed protocols for channel access and adaptive spreading were devised and evaluated for use in direct-sequence spread-spectrum packet radio networks that have no central controllers, access points, or base stations. Information theoretic bounds and tools have been derived that give performance benchmarks for practical protocols, provide analytical techniques for the minimization of resource consumption in tactical networks, and simplify the design of protocols for the adaptation of coding and spreading in direct-sequence spread-spectrum packet radios.

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Section: Scientific Progressmentioning

confidence: 87%

Section: Scientific Progressmentioning

confidence: 99%

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Cognitive Radio for Tactical Wireless Communication Networks

Pursley¹

2011

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“…Prior to iterative soft-decision decoding, the demodulator outputs are scaled by a metric derived from the post-detection signal quality (PDSQ) statistic, which is described in Section IV. It is shown in [6] that the PDSQ soft-decision decoding metric gives decoding performance comparable to that obtained from the log-likelihood ratio (LLR) metric [7], even if the LLR metric is given perfect channel-state information.…”

Section: Selection Of Code-modulation Combinationsmentioning

confidence: 99%

Information-Theoretic Methods for the Design and Evaluation of Adaptive Protocols for Direct-Sequence Spread-Spectrum Transmissions

Boyd

Pursley

2010

2010 IEEE Global Telecommunications Conference GLOBECOM 2010

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Adaptation of the code rate and spreading factor for direct-sequence spread-spectrum packet radio transmissions provides much higher throughput than if the code rate and spreading factor are fixed. A low-complexity protocol for packetby-packet adaptation can be obtained if receiver statistics that are developed during the demodulation of a packet are used to choose the code rate and spreading factor for the next packet. The design and evaluation of the protocol typically requires extensive simulations, especially for modern packet radio receivers that employ iterative decoding. We show that analytical methods based on Shannon capacity results greatly simplify the design of the adaptive protocol and provide good estimates of its throughput performance.

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“…A simple softdecision scaling metric that employs the PDSQ statistic is presented in [7]. The metric uses a fixed partition to scale the demodulator outputs prior to decoding.…”

Section: Introductionmentioning

confidence: 99%

Demodulator Statistics for Enhanced Soft-Decision Decoding in CDMA Packet Radio Systems

Boyd

Pursley

2010

2010 IEEE International Conference on Communications

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Next generation packet radio networks will have far greater processing capabilities than current radio systems. We propose and evaluate decoding techniques that make use of such capabilities to increase the probability of successful decoding. We propose a metric derived from statistics collected during demodulation in a binary CDMA receiver. We investigate several methods to apply the proposed metric to the demodulator's softdecision outputs prior to decoding. Our soft-decision decoding techniques are designed to mitigate the effects of interference from other signals in the frequency band. We compare the performance of our proposed metric to the log-likelihood ratio (LLR) metric, which requires that the mean signal level and noise variance are known for each bit position. Rather than attempt to estimate these parameters directly, our metric uses demodulator statistics and thus does not require pilot symbols or training sequences typically required by an LLR-based metric.

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A soft-decision scaling metric employing receiver statistics for direct-sequence spread-spectrum packet radio networks

Cited by 9 publications

References 7 publications

Cognitive Radio for Tactical Wireless Communication Networks

Cognitive Radio for Tactical Wireless Communication Networks

Information-Theoretic Methods for the Design and Evaluation of Adaptive Protocols for Direct-Sequence Spread-Spectrum Transmissions

Demodulator Statistics for Enhanced Soft-Decision Decoding in CDMA Packet Radio Systems

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