Capacity of PPM on Gaussian and Webb channels

Dolinar, S.; Hamkins, Jon; Pollara, F.

doi:10.1109/isit.2000.866708

Cited by 30 publications

(49 citation statements)

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“…On the other hand, the diversity achieved by the discrete input has a tradeoff with the target rate given by the Singleton bound. Note that (32) which implies that sufficiently large constellations can always achieve maximum diversity. The diversity characterization for discrete inputs provides a benchmark for the error performance of practical codes.…”

Section: Lemmamentioning

confidence: 99%

“…In optical wireless scintillation channels, we mainly deal with the received signal intensities (or instantaneous power signals), and not complex input symbols or complex fading realizations; thus the use of real amplitude modulation such as pulse-position modulation (PPM) is common [20]- [22], [32]. This means that the channel phase is not being considered in the detection (noncoherent detection) and therefore only the real-part of the complex Gaussian noise affects the decision.…”

Section: Extension To Optical Wireless Scintillation Distributionsmentioning

confidence: 99%

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Nearest Neighbor Decoding in MIMO Block-Fading Channels With Imperfect CSIR

Asyhari

Fàbregas

2012

IEEE Trans. Inform. Theory

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Abstract-This paper studies communication outages in multiple-input multiple-output (MIMO) block-fading channels with imperfect channel state information at the receiver (CSIR). Using mismatched decoding error exponents, we prove the achievability of the generalized outage probability, the probability that the generalized mutual information (GMI) is less than the data rate, and show that this probability is the fundamental limit for independent and identically distributed (i.i.d.) codebooks. Then, using nearest neighbor decoding, we study the generalized outage probability in the high signal-to-noise ratio (SNR) regime for random codes with Gaussian and discrete signal constellations. In particular, we study the SNR exponent, which is defined as the high-SNR slope of the error probability curve on a logarithmic-logarithmic scale. We show that the maximum achievable SNR exponent of the imperfect CSIR case is given by the SNR exponent of the perfect CSIR case times the minimum of one and the channel estimation error diversity. Random codes with Gaussian constellations achieve the optimal SNR exponent with finite block length as long as the block length is larger than a threshold. On the other hand, random codes with discrete constellations achieve the optimal SNR exponent with block length growing with the logarithm of the SNR. The results hold for many fading distributions, including Rayleigh, Rician, Nakagami-, Nakagami-and Weibull as well as for optical wireless scintillation distributions such as lognormal-Rice and gamma-gamma.Index Terms-Block-fading channels, channel state information, diversity, error exponent, generalized mutual information (GMI), imperfect channel state information, MIMO, multiple antenna, nearest neighbor decoding, outage probability, SNR exponent.

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Section: Lemmamentioning

confidence: 99%

Section: Extension To Optical Wireless Scintillation Distributionsmentioning

confidence: 99%

Nearest Neighbor Decoding in MIMO Block-Fading Channels With Imperfect CSIR

Asyhari

Fàbregas

2012

IEEE Trans. Inform. Theory

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“…Only when the bit-SNR is large enough, higher UC is achieved for larger M than smaller one. This is a surprising result, compared to those in previous research such as [3] and [2], in which equiprobable inputs are claimed to achieve the general capacity and capacity with larger M is always higher than that with smaller M for every bit-SNR. A possible reason for the difference is that in our research, the values of input symbols involved in capacity computation are not those in [1, M] but the sample points of autocorrelation function dependent on specific monocycle.…”

Section: Numerical Resultscontrasting

confidence: 71%

“…PPM has been used in wireless infrared and optical communications for a long time, and the capacity of a PPM system has been well-founded based on a so-called "pure PPM model", that is, an AWGN channel model with power-constrained discrete M -PPM inputs and unconstrained continuous outputs [2]. Capacity analysis of UWB systems can appeal to these results to make an estimation of capacity as in [3].…”

Section: Introductionmentioning

confidence: 99%

New results on the capacity of M-ary PPM ultra-wideband systems

Zhang

Kennedy

Abhayapala

IEEE International Conference on Communications, 2003. ICC '03.

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Abstract-In this paper, some new results on the capacity of a typical M -ary pulse position modulation (M -PPM) time hopping (TH) Ultra-Wideband (UWB) system are presented. Previous results using a "pure PPM model" are proven to exaggerate the real capacity of a UWB system. Based on an extended model containing correlator and soft decision decoding, the capacity is evaluated in the single-user case and in the case of a system with asynchronous multiple user interference (MUI) when the inputs are equiprobable. It is found that only when bit-signal-to-noise ratio (bit-SNR) is high enough, larger M leads to higher capacity; and for a specific M , the optimal values of PPM time offset parameter T d , which maximize the capacity, are independent of bit-SNR. The influence of MUI on capacity is detrimental, especially in the case of high bit-SNR.

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“…Based on the results for optical channels in [7], the channel capacity of an M-ary pulse position modulation (PPM) UWB system was evaluated in [8] for additive white Gaussian noise (AWGN) channels with a single user. For the same system, authors in [9] showed that the channel capacity is highly affected by pulse shapes.…”

Section: Introductionmentioning

confidence: 99%