trellis-coded modulation (TCM) [1] offers a theoretical gain of more than 3 dB for an additive white Gaussian noise (AWGN) channel without an increase in signal bandwidth and without any alteration of the transmitted ...
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trellis-coded modulation (TCM) [1] offers a theoretical gain of more than 3 dB for an additive white Gaussian noise (AWGN) channel without an increase in signal bandwidth and without any alteration of the transmitted information rate. This letter describes the simulation of TCM for an INTELSAT VI satellite link, It shows that the use of a simple four-state code can give a gain of up to 2.7 dB.
In high-rate wireless LAN, complementary code keying (CCK) is adopted in the IEEE 802.11b standard to support data rates up to 11 Mbps, much higher than the 2-Mbps data rate in the previous wireless LAN standard. Due ...
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In high-rate wireless LAN, complementary code keying (CCK) is adopted in the IEEE 802.11b standard to support data rates up to 11 Mbps, much higher than the 2-Mbps data rate in the previous wireless LAN standard. Due to less-than-ideal characteristics of the CCK codewords, the CCK performs quite poorly in large-delay-spread multipath channels, In this letter, a new modulation scheme that combines the trellis coding with the CCK modulation is proposed. This scheme is shown, through simulation, to achieve much better error rate performance in medium-to-large channel delay spread environments.
An upper bound on the minimum squared distance of trellis codes by packing Voronoi cells is derived, and we compare this bound with previously known bounds. The bound is tight to search results for coset codes with a ...
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An upper bound on the minimum squared distance of trellis codes by packing Voronoi cells is derived, and we compare this bound with previously known bounds. The bound is tight to search results for coset codes with a small number of states.
The application of the well-known technique of trellis Coded Modulation to coherent optical communications using Polarization Shift Keying (POLSK) is described and analyzed. The resulting receiver is formed by a front...
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The application of the well-known technique of trellis Coded Modulation to coherent optical communications using Polarization Shift Keying (POLSK) is described and analyzed. The resulting receiver is formed by a front-end which performs the heterodyne detection and the Stokes parameter extraction;cascaded with an electronic Viterbi processor operating the maximum likelihood estimate of the transmitted sequence. Results in terms of the error event probability using optimum as well as a simpler suboptimum branch metric show power gains on the order of 3-4 dB, at the expense of a reasonable increase in complexity, only concerning the processing in the electronic domain. These coding gains are not lost even in the presence of high levels of phase noise, to which POLSK in general is highly insensitive.
The pairwise error probability for a trellis-coded MPSK system with imperfect phase reference at high S/N is derived. These results are used to study the effect of phase offset, phase jitter and imperfect differential...
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The pairwise error probability for a trellis-coded MPSK system with imperfect phase reference at high S/N is derived. These results are used to study the effect of phase offset, phase jitter and imperfect differential detection on trellis-coded MPSK.
For time-division-multiplexed coded modulation schemes with unequal error protection (UEP) proposed in the literature, the receiver requires several independent Viterbi decoders to decode all classes of data. A new UE...
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For time-division-multiplexed coded modulation schemes with unequal error protection (UEP) proposed in the literature, the receiver requires several independent Viterbi decoders to decode all classes of data. A new UEP coded modulation scheme is proposed which has the advantages that decoding can be done by using a single slightly modified Viterbi decoder and that good coding gains can still be provided. Some new codes are presented with a rate of four bit/2D and percentage of important data ranging from 31.25 to 72.92%, which find potential applications in the envisioned digital broadcast of high-definition television signals. Excellent coding gains from 5.4 to 7.2dB for the important data, as verified by simulations, can be provided with our scheme by using only eight-state codes.
Different transceiver structures for the proposed high-bit-rate (800 kbit/s) digital subscriber loop transmission interface are analysed. The simulation results presented in the paper demonstrate that high-bit-rate ac...
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Different transceiver structures for the proposed high-bit-rate (800 kbit/s) digital subscriber loop transmission interface are analysed. The simulation results presented in the paper demonstrate that high-bit-rate access with a considerable performance margin is feasible if baseband transceivers with appropriate equalisation and simple trellis coding are used. Initial results also indicate that more complicated bandpass transceivers with similar equalisation and trellis coding do not provide any clear performance advantage.
This paper examines the implementation of multi-level amplitude modulation enforced by trellis coding in a downlink non-orthogonal multiple access channel for visible light communication (VLC). The non-orthogonal tran...
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This paper examines the implementation of multi-level amplitude modulation enforced by trellis coding in a downlink non-orthogonal multiple access channel for visible light communication (VLC). The non-orthogonal transmission is applied using superposition coding and successive interference cancellation with the support of a trellis decoder. The VLC is addressed by a channel model according to Lambert. Two levels of maximum likelihood signal detection are observed and compared, each for corresponding 4 and 8 trellis-coded modulation (TCM). The power ratio allotment is examined to investigate the system performance in the bit error rate. The simulation showed that a threshold of power ratio is needed to ensure good performance of signal detection. Further simulation with successive detection had shown effective results for up to three users.
The Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm is an important channel decoding method. We extend it to trellis rate-distortion data compression. Beginning from source coding principles, the derivation of the algorithm...
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The Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm is an important channel decoding method. We extend it to trellis rate-distortion data compression. Beginning from source coding principles, the derivation of the algorithm avoids channel coding or soft output ideas. The encoder does not use entropy coding;equiprobable reproducer letters are emphasized since these maximize entropy. The BCJR method is demonstrated by tests of a tail-biting variant. It performs much better than the ordinary Viterbi algorithm for short and medium blocks. However, the improvement stems from tail biting;the role of the BCJR is to achieve tail biting in a relatively simple way. Some issues that arise with tail biting are explored. It is shown that there is an optimal trellis state size for each block length.
Random overlapping pulse-position modulation (OPPM) sequences result in an unrecoverable error floor on both the probability of erroneous synchronization and the probability of symbol error when only chip synchronizat...
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Random overlapping pulse-position modulation (OPPM) sequences result in an unrecoverable error floor on both the probability of erroneous synchronization and the probability of symbol error when only chip synchronization is present. It is known, however, that for a given sequence length M, a subset of the set of all possible sequences is synchronizable in the sense that in the absence of noise, the receiver can correctly symbol synchronize by observing M or more symbol intervals. In this paper we design finite-state machines and codes over a J-ary alphabet, which produce sequences with the property that every subsequence of length L is synchronizable. Some of the codes, in addition to being synchronizable, produce a coding gain. For an optical Poisson channel we introduce joint synchronization and detection algorithms that utilize the memory in the encoded sequences to produce joint estimates of timing and sequences. Their performance is analyzed through simulations and analytical results.
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