Showing papers on "Bandwidth expansion published in 1992"
TL;DR: It is shown that this coding technique can be viewed as a generalization of a well-known procedure for binary signaling: the concatenation of convolutional codes and inner block codes that are tuned to the channel polynomial that results in high coding gains with moderate complexity if some bandwidth expansion is accepted.
Abstract: The problem of trellis coding for multilevel baseband transmission over partial response channels with transfer polynomials of the form (1+or-D/sup N/) is addressed. The novel method presented here accounts for the channel memory by using multidimensional signal sets and partitioning the signal set present at the noiseless channel output. It is shown that this coding technique can be viewed as a generalization of a well-known procedure for binary signaling: the concatenation of convolutional codes and inner block codes that are tuned to the channel polynomial. It results in high coding gains with moderate complexity if some bandwidth expansion is accepted. >
8 citations
TL;DR: In this article, the authors extend the application of this detection technique to the coded Steiner-triple pulse format, which has recently proved its outstanding features and obtain an improved performance with respect to RSPPM, in addition to modest bandwidth expansion and efficient transmission bandwidth.
Abstract: Optical communication has recently been given a great deal of attention because of its anticipated contribution in increasing our data transmission capability. δmax detection of Reed-Solomon coded PPM (RSPPM) signaling has been seen as a reliable detection technique [1]. In this article we extend the application of this detection technique to the coded Steiner-triple pulse format, which has recently proved its outstanding features [2, 3]. It is shown here that an improved performance (with respect to RSPPM), in addition to modest bandwidth expansion and efficient transmission bandwidth, are obtained.
3 citations
2 citations
01 Feb 1992
TL;DR: The project's objective is to develop an advanced high speed coding technology that provides substantial coding gains with limited bandwidth expansion for several common modulation types and is applicable to several continuous and burst communication environments.
Abstract: The project's objective is to develop an advanced high speed coding technology that provides substantial coding gains with limited bandwidth expansion for several common modulation types. The resulting technique is applicable to several continuous and burst communication environments. Decoding provides a significant gain with hard decisions alone and can utilize soft decision information when available from the demodulator to increase the coding gain. The hard decision codec will be implemented using a single application specific integrated circuit (ASIC) chip. It will be capable of coding and decoding as well as some formatting and synchronization functions at data rates up to 300 megabits per second (Mb/s). Code rate is a function of the block length and can vary from 7/8 to 15/16. Length of coded bursts can be any multiple of 32 that is greater than or equal to 256 bits. Coding may be switched in or out on a burst by burst basis with no change in the throughput delay. Reliability information in the form of 3-bit (8-level) soft decisions, can be exploited using applique circuitry around the hard decision codec. This applique circuitry will be discrete logic in the present contract. However, ease of transition to LSI is one of the design guidelines. Discussed here is the selected coding technique. Its application to some communication systems is described. Performance with 4, 8, and 16-ary Phase Shift Keying (PSK) modulation is also presented.
2 citations
TL;DR: In this paper, a Reed-Solomon coded triple multipulse model is extended to the Steiner quadruple pulse system (SQS) considering a threshold demodulation scheme for a fully degraded optical channel.
Abstract: In references [1, 2], triple multipulse position modulated (TPPM) signaling has been introduced as a very reliable format for optical communication channels. In this article, such a multipulse model is extended to the Steiner quadruple pulse system (SQS). Considering a threshold demodulation scheme for a fully degraded optical channel, performance of the Reed-Solomon coded model is evaluated and compared to the standard coded PPM, when similar information efficiency and closest bandwidth expansion are allowed. The gained results are very interesting. © 1992 John Wiley & Sons, Inc.
11 Oct 1992
TL;DR: It is observed that the ternary alphabet yields the best performance among the systems employing various alphabet sizes, when the bandwidth is fixed, and nonbinary systems outperform the binary system only above a threshold.
Abstract: Communications systems with various alphabet sizes for transmission of video signals are compared on the basis of equal information rate, bandwidth, and average power. Two cases are considered: when the bandwidth constraint is tight and when it is somewhat loose. It is observed that the ternary alphabet yields the best performance among the systems employing various alphabet sizes, when the bandwidth is fixed. Nonbinary systems outperform the binary system only above a threshold. For the case when the bandwidth can be expanded, there is a threshold above which a nonbinary system is superior to the binary system. The threshold values in this case are larger than for the fixed bandwidth case and depend on the bandwidth expansion factor and the size of the alphabet. >