Double repetition code exhibits unique properties when combined with precoded generalized minimum-shift keying signals of up to two symbol period pulse duration. It is shown that using two stages of channel encoding, ...
详细信息
Double repetition code exhibits unique properties when combined with precoded generalized minimum-shift keying signals of up to two symbol period pulse duration. It is shown that using two stages of channel encoding, the last being a double repetition code, the code design for such modulation scheme simplifies. Also, it is shown that the nonlinear continuous-phase frequency-shift keying modulator can be replaced by a simple linear I-Q modulator to generate the same coded signals. The detection problem for the recovery of the symbols sequence from the decision variables is shown to be one corresponding to memoryless modulation, avoiding the use of the maximum likelihood sequence detection.
Combining some of the best terrestrial and satellite systems' characteristics, high altitude platforms (HAPs) have recently emerged as an alternative solution for the provision of broadband services. Characterised...
详细信息
Combining some of the best terrestrial and satellite systems' characteristics, high altitude platforms (HAPs) have recently emerged as an alternative solution for the provision of broadband services. Characterised by challenging propagation conditions in the allocated frequency bands, they require efficient utilisation of radio interface in order to make best use of the available spectrum. This paper analyses possible utilisation of DVB-S2 standard on HAPs, focusing on the performance of its adaptive coding and modulation (ACM) procedures as a mean of maximizing the link reliability and throughput. Two distinct operating scenarios are addressed, one assuming static channel conditions with the applied rain fading and the other representing mobile channel conditions along a representative railway track We show that by considering only a subset of transmission modes (MODCODs) defined by the DVB-S2 standard, the system could be optimized in terms of achievable spectral efficiency as well as in terms of implementation complexity. A procedure for optimal MODCOD subset selection is proposed, taking into account the predefined switching thresholds and round-trip time delay.
Adaptive coding and modulation are well known techniques for enhancing the performance of systems transmitting over quasi-static fading channels. Especially their application in OFDM based systems promises gains in sp...
详细信息
Adaptive coding and modulation are well known techniques for enhancing the performance of systems transmitting over quasi-static fading channels. Especially their application in OFDM based systems promises gains in spectral efficiency. In former work we presented an efficient method for the joint optimization of code rate and modulation formats if rate-compatible punctured codewords are mapped onto sub-symbols with heterogeneous channel quality and modulation formats. In this paper, we demonstrate the application of our scheme to MIMO techniques. More specifically, we investigate non-orthogonal spatial multiplexing schemes in bit-interleaved coded OFDM systems. The techniques are evaluated within the context of the OFDMA/TDMA system designed within the EU FP6 Integrated Project WINNER.
This paper demonstrates the application of binary convolutional coding applied to the bandwidth efficient, constant envelope modulation developed by Resnikoff and Tigerman. The modulation waveform and phase form are p...
详细信息
ISBN:
(纸本)9781424429400
This paper demonstrates the application of binary convolutional coding applied to the bandwidth efficient, constant envelope modulation developed by Resnikoff and Tigerman. The modulation waveform and phase form are presented with the corresponding bit error performance expression for uncoded M-ary modulation. Probability of information bit error performance analysis is provided for M-ary modulation with binary convolutional coding with hard and soft decision Viterbi decoding. Expected performance bounds and coding gains are determined using the probability of information bit error performance analysis for M = 8 modulation with rate 1/3 binary convolutional codes, and are validated by numerical simulations. Near optimum path metrics are devised for M-ary modulation with binary convolutional codes with soft decision decoding.
In this treatise, a jointly optimized bit interleaved coded modulation using Iterative decoding (BICM-ID) and Luby transform (LT) coding scheme was proposed for the sake of attaining the best possible performance, whe...
详细信息
In this treatise, a jointly optimized bit interleaved coded modulation using Iterative decoding (BICM-ID) and Luby transform (LT) coding scheme was proposed for the sake of attaining the best possible performance, when communicating over the wireless Internet. This scheme is particularly attractive when handling packetized wireless Internet data traffic received over wireless channels inflicting both statistically multiplexing induced packet erasure and packet corruption imposed by the channel without retransmitting the corrupted packets. A LLR-based estimation packet reliability algorithm was proposed to assist the LT decoder in recovering all the transmitted packets. Furthermore, the bit-to-sphere-packing-symbol mapping scheme was optimized for achieving error free LT decoding at the lowest possible Eb/No value rather than for approaching the channel's capacity. These two design philosophies require different mapping schemes. Finally, differential space time coding (DSTBC) was employed for combatting the effects of fading and provided spatial diversity at the same time. The LT code's packet length was also carefully chosen to strike a good balance between the affordable complexity and the achievable performance.
For the seamless video streaming, the bandwidth variation should be considered to control the transmission rate. The packet pair probing technique (PPPT) can be utilized to measure the bandwidth of the network. To ada...
详细信息
For the seamless video streaming, the bandwidth variation should be considered to control the transmission rate. The packet pair probing technique (PPPT) can be utilized to measure the bandwidth of the network. To adapt the PPPT to the video streaming over the high speed downlink packet access (HSDPA), we experimentally investigate the relationship between the actual available bandwidth (AB) of the HSDPA network and the channel capacity estimated by the PPPT. Using this relationship, we propose an efficient real-time video streaming method. Experimental results show that the proposed method improves the performance of the video streaming over the HSDPA network.
A new union bound on the bit error probability of bit-interleaved space-time (BI-ST) coded systems is derived. Unlike existing performance analysis tools for BI-ST systems, the new bound provides a general framework f...
详细信息
A new union bound on the bit error probability of bit-interleaved space-time (BI-ST) coded systems is derived. Unlike existing performance analysis tools for BI-ST systems, the new bound provides a general framework for analysing the performance of BI-ST systems employing finite interleaver sizes. The derivation is based on the uniform interleaving assumption of the coded sequence prior to transmission over multiple antennas. The new bound is a function of the distance spectrum of the code, the signal constellation used and the space-time (ST) mapping scheme. The bound is derived for a general BI-ST coded system and applied to two specific examples, namely, the BI space-time coded modulation and the BI space-time block codes. Results show that the analysis provides a close approximation to the BI-ST performance for a wide range of signal-to-noise ratios. The analysis can also accurately characterise the performance differences between different interleaver sizes, which is a breakthrough in the analysis of BI-ST coded systems.
A new set of 136 binary sequences of length 16 applied to reducing the peak-to-mean envelope power ratio of orthogonal frequency division multiplexing systems is reported. A non-systematic encoder is developed. This s...
详细信息
A new set of 136 binary sequences of length 16 applied to reducing the peak-to-mean envelope power ratio of orthogonal frequency division multiplexing systems is reported. A non-systematic encoder is developed. This set of sequences can be used with the existing 384 binary Golay sequences of 16. The resultant set will consists of 512 sequences, an integer power of 2, which expedite implementation.
Broadband fixed wireless access ( BFWA) systems enable services such as high-speed data communication, high quality voice/video conferencing and high-speed internet access in areas where a wired link is not possible. ...
详细信息
Broadband fixed wireless access ( BFWA) systems enable services such as high-speed data communication, high quality voice/video conferencing and high-speed internet access in areas where a wired link is not possible. However, the BFWA channel is a slow-fading channel having deep frequency-selective fading caused by clusters of scatterers in the environment that introduce inter-symbol interference ( ISI) at the receiver. Low density parity check ( LDPC) codes, optimised for the single-input single-output BFWA channel, are designed using the structured balance incomplete block design method. The use of both quadrature phase shift keying ( QPSK) and 16-quadrature amplitude modulation ( 16-QAM) are investigated theoretically. To help overcome the ISI effects of the channel, equalisation techniques are employed separately with LDPC decoding for a system employing QPSK and 16-QAM modulation schemes. The equaliser single carrier approach is then replaced with orthogonal frequency division multiplexing ( OFDM) and the performance of these two approaches is evaluated in terms of bit-error rate. The simulation results show that equalisation with LDPC coding has a measurable performance gain over LDPC coding with OFDM.
As PMD compensation has become a very intense subject of research in recent years, the achievement of simple PMD compensators based on a feedback signal is a key issue. As PMD compensation uses a feedback indicator fo...
详细信息
As PMD compensation has become a very intense subject of research in recent years, the achievement of simple PMD compensators based on a feedback signal is a key issue. As PMD compensation uses a feedback indicator for system performance evaluation, such feedback signals must reproduce the DGD variations with time. In this paper, the correlation between DGD and different feedback signals is studied with a new method. This method is applied for various modulation schemes, leading to well-known results. By applying the method to the electrical and optical duobinary formats, it is shown that for duobinary signals, the DOP feedback signal shows the best correlation with instantaneous DGD value. Such a behavior of duobinary format is very interesting since duobinary modulation schemes are now considered for systems upgrades or mixed architectures (10 Gbit/s-40 Gbit/s on the same link). In such systems, PMD compensation has to be bit-rate independent which is available with the DOP as feedback indicator.
暂无评论