We present a design method of the simulation probability density function for a trellis-coded modulation (TCM) in an impulsive noise environment. The upper bound evaluation method for the TCM scheme cannot be applied ...
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We present a design method of the simulation probability density function for a trellis-coded modulation (TCM) in an impulsive noise environment. The upper bound evaluation method for the TCM scheme cannot be applied to the lognormally distributed impulsive noise, since the Chernoff bound cannot be defined. Thus the error probability can only be estimated by a computer simulation. For an evaluation of a low error probability, importance sampling (IS) is an efficient technique. A design method of the simulation probability density function, which plays an important role in IS, is proposed for the noise. The effectivity is shown by a numerical example.
We present here design techniques for trellis-coded vector quantizers with symmetric codebooks that facilitate low-complexity quantization as well as partitioning into equiprobable sets for trellis coding, The quantiz...
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We present here design techniques for trellis-coded vector quantizers with symmetric codebooks that facilitate low-complexity quantization as well as partitioning into equiprobable sets for trellis coding, The quantization performance of this coder on the independently identically distributed (i.i.d.) Laplacian source matches the performance of trellis-based scalar-vector quantization (TB-SVQ) [1], but requires less computational complexity.
Reduced-state sequence detection (RSSD) reduces the state trellis of a channel code by forming the states into classes. States within a class are such that paths into the states lie further than a distance parameter d...
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Reduced-state sequence detection (RSSD) reduces the state trellis of a channel code by forming the states into classes. States within a class are such that paths into the states lie further than a distance parameter d from each other. An RSSD decoder retains only one survivor per class at each trellis level. We apply RSSD to ordinary binary convolutional codes. We first give a class-forming algorithm that finds the greatest reduction. It turns out that no commonly tabulated good code benefits from RSSD. However, RSSD is an effective way to repair weaker codes, such as Quick Look-In and RCPC codes. Finally, we show that RSSD cannot be more efficient than the M-algorithm.
Space-time coding is well established for high data rate communications over wireless channels with perfect channel state information. On the other hand, the case where the channel state information is unknown has rec...
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Space-time coding is well established for high data rate communications over wireless channels with perfect channel state information. On the other hand, the case where the channel state information is unknown has received limited attention. Recently, a new signaling scheme called unitary space-time modulation that is suitable for the latter case has been proposed. In this paper, we describe the use and design of trellis-coded space-time modulation schemes that use unitary space-time constellations. We construct these codes using a novel suboptimal code design criteria and study the performance of trellis-coded unitary space-time modulation for block fading channels under the assumption of no channel state information. Simulation results show Chat the proposed schemes improve the performance compared to uncoded transmission with the same spectral efficiency. The results are also compared with the turbo-coded modulation scheme Bahceci, (2002) and the differential detection scheme described Jafarkhani, (2001) under the same assumptions.
The performance of an 8/9 rate Matched Spectral Null (MSN) code is analyzed on the PR4 magnetic recording channel with Additive White Gaussian Noise (AWGN) at the sensor. The high rate is achieved with a fixed charge ...
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The performance of an 8/9 rate Matched Spectral Null (MSN) code is analyzed on the PR4 magnetic recording channel with Additive White Gaussian Noise (AWGN) at the sensor. The high rate is achieved with a fixed charge constraint code of block length N=27 on each of the PR4 channel's dicode interleaves, A simplified semi-analytic method for MSN codes that approximates the constants multiplying the Q function for certain error event types is introduced and validated by simulations. The 8/9 rate MSN/PR4 system was compared to a normal 16/17 rate code with PR4 and EPR4 detectors for a range of user densities. The MSN/PR4 system has less than 0.9dB net coding gain for user densities above 2.25, and it's inferior to simple EPR4 at user densities above 1.9.
trellis-coded quantization is generalized to allow a vector reproduction alphabet. Three encoding structures are described, several encoder design rules are presented, and two design algorithms are developed. It is sh...
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trellis-coded quantization is generalized to allow a vector reproduction alphabet. Three encoding structures are described, several encoder design rules are presented, and two design algorithms are developed. It is shown that for a stationary, ergodic vector source, if the optimized trellis-coded vector quantization reproduction process is jointly stationary and ergodic with the source, then the quantization noise is zero-mean and of variance equal to the difference between the source variance and the variance of the reproduction sequence. Several examples illustrate the encoder design procedure and performance.
Multicarrier trellis-coded modulation is known to be effective in land mobile delay-sensitive speech communications, since it can achieve frequency diversity by multicarrier and trellis coding without interleaving. Re...
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Multicarrier trellis-coded modulation is known to be effective in land mobile delay-sensitive speech communications, since it can achieve frequency diversity by multicarrier and trellis coding without interleaving. Recently, multicarrier trellis-coded 8PSK using frequency hopping (FH) has been proposed to reduce the fading correlation of the received signal and increase the error correction capability of multicarrier trellis-coded systems. In cellular communication systems, frequency reuse is employed to achieve good spectral efficiency, although it depends on the level of the cochannel interference (CCI). Interference immunity decoding methods with interleaving based on randomizing the CCI levels and adjusting the minimum Euclidean distance according to the weighted value by using the estimated CCI level per symbol have been proposed. However, the use of interleaving may cause time delays. In this paper, we propose an interference immunity decoding method for multicarrier trellis-coded slow-FH/16QAM without using interleaving. In our proposed scheme, we estimate the CCI using space symbols inserted in several slots and modify the branch metric according to the weighted value by using the estimated CCI level per symbol. Multiple carriers using frequency hopping are employed to prevent excess time delay by randomizing the interference level without interleaving. The BER performance of the proposed decoding method is investigated by computer simulation. It is shown that the proposed decoding method is effective in suppressing the effects of CCI in fading channels. (C) 1999 Scripta Technica.
We evaluate a new class of rate-distortion codes based on simple linear congruential recursions. Codes are demonstrated for the memoryless Uniform, Gaussian, Laplacian and Gamma sources, whose performance often exceed...
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We evaluate a new class of rate-distortion codes based on simple linear congruential recursions. Codes are demonstrated for the memoryless Uniform, Gaussian, Laplacian and Gamma sources, whose performance often exceeds that so far reported in the literature, including that for TCQ codes. At a source coding rate of one bit per sample the performance at 512 states is 0.24 dB from the Shannon limit for the memoryless Gaussian source.
Spatial modulation (SM), in which multiple antennas are used to convey information besides the conventional M-ary signal constellations, is a new multiple-input multiple-output (MIMO) transmission technique, which has...
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Spatial modulation (SM), in which multiple antennas are used to convey information besides the conventional M-ary signal constellations, is a new multiple-input multiple-output (MIMO) transmission technique, which has recently been proposed as an alternative to V-BLAST (vertical Bell Labs layered space-time). In this paper, a novel MIMO transmission scheme, called spatial modulation with trellis coding (SM-TC), is proposed. Similar to the conventional trellis coded modulation (TCM), in this scheme, a trellis encoder and an SM mapper are jointly designed to take advantage of the benefits of both. A soft decision Viterbi decoder, which is fed with the soft information supplied by the optimal SM decoder, is used at the receiver. A pairwise error probability (PEP) upper bound is derived for the SM-TC scheme in uncorrelated quasi-static Rayleigh fading channels. From the PEP upper bound, code design criteria are given and then used to obtain new 4-, 8- and 16-state SM-TC schemes using quadrature phase-shift keying (QPSK) and 8-ary phase-shift keying (8-PSK) modulations for 2, 3 and 4 bits/s/Hz spectral efficiencies. It is shown via computer simulations and also supported by a theoretical error performance analysis that the proposed SM-TC schemes achieve significantly better error performance than the classical space-time trellis codes and coded V-BLAST systems at the same spectral efficiency, yet with reduced decoding complexity.
This paper derives the upper and lower bounds on the minimum distance of 4-ary circular trellis-coded modulation using a simplex signal constellation. The bounds are shown to be tight and reachable, and the code is sh...
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This paper derives the upper and lower bounds on the minimum distance of 4-ary circular trellis-coded modulation using a simplex signal constellation. The bounds are shown to be tight and reachable, and the code is shown to achieve simplex distance between parallel paths at each stage of the trellis. (C) 2002 Elsevier Science (USA).
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