Channels with block interference

Abstract-Queuing theory allows the design of communication links that can provision for Quality of Service (QoS) in time-varying channels, such as mobile wireless channels, by considering an idealized queuing system that abstracts out the physical layer. Similarly, information theory allows the design and analysis of channel codes that can guarantee low decoding error probability by adapting to the time-varying channel. Whereas other researchers have attempted cross-layer design methods that combine these two approaches, these have been limited to specific choices of practical channel codes. There have been few attempts to combine these two theories to specify the ultimate limit of delay-constrained communications. This paper presents an approach that obtains a QoS exponent, by combining the queuing and information theoretic models; in particular, by considering information-theoretically optimal channel codes. Calculations show that such a joint approach yields substantial improvement in QoS performance in a variety of communication scenarios.

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“…© ¥ and then trivially extend our result to block fading channels [13], which have blocks of equal gain.…”

Section: Problem Formulationsupporting

confidence: 60%

An information-theoretic approach to queuing in wireless channels with large delay bounds

Negi

Goel

IEEE Global Telecommunications Conference, 2004. GLOBECOM '04.

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“…The capacity of general channels with block memory is considered in [3] and [4]. We consider systems that employ slow frequency hopping with orthogonal modulation, noncoherent demodulation, multiple modulation symbols per dwell interval, and error-control coding with softdecision decoding.…”

Section: Discussionmentioning

confidence: 99%

Capacity limits and performance results for frequency-hop transmission over partial-band noise channels

Pursley

Royster

2008

2008 Information Theory and Applications Workshop

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Abstract-Capacity limits and throughput results are evaluated for slow frequency-hop transmission over channels in which the bandwidth of the partial-band noise may vary but the total power in the noise is constant. The system employs orthogonal modulation, noncoherent demodulation, and error-control coding with iterative decoding. We find that the capacity limits for the system and the performance results for turbo product codes and low-density parity-check codes show that the throughput can be a nonmonotonic function of the bandwidth of the partial-band noise. We discuss how such nonmonotonicity affects the design of adaptive-rate coding systems. I. SUMMARYFrequency-hop spread spectrum is a communications technique that is effective against channel disturbances such as narrowband interference, hostile jamming, frequency-selective fading, frequency-hop multiple-access interference, and other types of partial-band interference. We consider slow frequencyhop communications in which each packet is divided into multiple segments and one segment is transmitted per hop. If there is more than one modulation symbol per dwell interval, the system may experience block interference. That is, if a dwell interval is in a frequency slot with strong interference, then all the symbols of the dwell interval are corrupted. The benefits of error-control coding in this type of frequency-hop system are discussed in [1]. The combination of error-control coding, interleaving, and soft-decision iterative decoding is particularly effective in mitigating the effects of partial-band interference.Expressions and numerical results for capacity limits of M-ary orthogonal modulation, noncoherent demodulation, and hard-decision decoding with multiple modulation symbols per dwell interval are given in [2]. The capacity of general channels with block memory is considered in [3] and [4]. We consider systems that employ slow frequency hopping with orthogonal modulation, noncoherent demodulation, multiple modulation symbols per dwell interval, and error-control coding with softdecision decoding. We have evaluated numerical capacity limits for such systems. In addition, we have obtained the corresponding performance results for binary and nonbinary modulation as well as binary and nonbinary error-control codes.Every frequency slot contains thermal noise, but only a fraction of the bandwidth experiences additional interference. This partial-band interference is modeled as having a fixed power regardless of the fraction ρ of the bandwidth it occupies. Thus, the interference density decreases as ρ increases.A useful performance measure of an error-control code is its probability of code word error as a function of ρ. From such results, the average throughput as a function of ρ can be computed. We have evaluated the throughput for binary turbo product codes and nonbinary LDPC codes. Using capacity bounds, we have also determined the throughput performance of capacity-achieving codes as a function of the fractional bandwidth.In our evaluations of the tu...

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“…It is also possible to interpret this average capacity formula by using the result of [11] on the capacity of the channels with side information at the receiver only. In fact, if the same input distribution maximizes the mutual information for all the channel states and also the sequence of the channel states are i.i.d.…”

Section: Problem Formulation and Notationsmentioning

confidence: 99%

“…In fact, if the same input distribution maximizes the mutual information for all the channel states and also the sequence of the channel states are i.i.d. then it has been shown that the capacity is given by average capacity formula over all channel states [11].…”

Section: Problem Formulation and Notationsmentioning

confidence: 99%

The capacity of average and peak power constrained fading channels with channel side information

Khojastepour

Aazhang

2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733)

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Abstract-We derive the ergodic capacity of discrete-time fading channel with additive Gaussian noise subject to both peak and average power constraint. The average power can be interpreted as the cost that we incur to achieve a certain rate. On the other hand, the motivation of this analysis comes from the fact that there is also a peak power limitation in practical communication system. It is been shown that the optimal power adaption is no longer water-filling or constant power adaption which is the case where there is no limitation on the peak power. The numerical results show that the importance of peak power constraint become negligible for relatively low available average power, while it is limiting the capacity to be finite even as available average power goes to infinity.

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Channels with block interference

Cited by 341 publications

References 7 publications

An information-theoretic approach to queuing in wireless channels with large delay bounds

An information-theoretic approach to queuing in wireless channels with large delay bounds

Capacity limits and performance results for frequency-hop transmission over partial-band noise channels

The capacity of average and peak power constrained fading channels with channel side information

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