Fan Pingyi

Network coding-aware cooperative relaying for downlink cellular relay networks

In this paper, we first overview some traditional relaying technologies, and then present a Network Coding-Aware Cooperative Relaying (NC2R) scheme to improve the performance of downlink transmission for relay-aided cellular networks. Moreover, systematic performance analysis and extensive simulations are performed for the proposed NC2R and traditional relaying and non-relaying schemes. The results show that NC2R outperforms conventional relaying and non-relaying schemes in terms of blocking probability and spectral efficiency, especially for cell-edge users. Additionally, the location selections for relays with NC2R are also discussed. These results will provide some insights for incorporating network coding into next-generation broadband cellular relay mobile systems.

Design of interpolation filter for all digital receiver—On the interpolation problem of full response modulation signals

All digital implementation of receiver is a main topic on digital communication recently. The design of interpolation filter is one of the important problems for all digital implementation of receiver. In this paper, for full response linear modulation signal, a interpolation criterion is proposed. An interpolation formula is presented on bandwidth-limited transmission signal. For example, using the raised cosine roll off function as the system pulse response, the feasibility and effectiveness on the interpolation formula are certified by theoretical and numerical analysis. The computer simulation result on 16-QAM signal is given.

Temporal characteristics of the queueing process of buffer-aided wireless communications

Due to the fading property of wireless channels, the instant transmission capability of a fading channel, i.e., the instantaneous channel capacity, will change randomly along time. Usually, a finite size buffer is needed at the transmitter to match instant channel capacity with the source data stream. This paper is focused on the queuing process in the buffer. The temporal characteristics of the queueing process in the buffer are investigated, for a buffer-aided communication over block Rayleigh fading channel, in the low signal-to-noise ratio regime. Particularly, the average absorbing time for the buffer to transfer from empty state to overflow sate and from overflow state to empty state, as well as the stable working time in which neither buffer empty nor buffer overflow happens are derived. Theoretical and numerical results show that increasing the buffer size and traffic load properly will improve the efficiency of the transmission.

A modified Doppler corrected demodulation algorithm and its DSP implementation

The problem of Doppler frequency shift (DFS) correction is one of the most important problems in the digital mobile communications. This paper discusses the Doppler corrected demodulation algorithm proposed in Simon and Divsalar (1989), and modifies some parts of the algorithm concerning the hardware implementation; for example, the bandwidth of the receiver front filter, the method of DFS correction and the digital post-processing part, etc. The modified algorithm has been realized on the TMS320C50 developing board. The results of hardware experiments and computer simulations have shown that our modified algorithm is effective.

Some new results on Z transform

In signal analysis and processing, the Z transform plays the same-important role in the discrete signal system as that of the Laplace transform in a continuous signal system. The limitation of the application of the Z transform is analysed. A new concept of the wide sense Z (WSZ) transform for a bandlimited signal is proposed, some new results is obtained, and the transform theory is expanded. In practical applications, some problems which are difficult to solve with the traditional Z transform can be solved easily by the proposed theory.

A matrix algorithm for computing the free space distance of TCM codes sequence

In this paper, the problem of computing the free distance of TCM code sequences has been discussed. A new algorithm, the matrix algorithm, is proposed, and the step-number estimation problem for state transmission to compute the free distance of the TCM code sequences has been theoretically solved. The matrix algorithm is derived from the Viterbi algorithm, and is an implementation of the Viterbi algorithm in the form of a matrix. Compared with other algorithms, the matrix algorithm has two advantages: (1) the explicit solution, and its relatively lower complexity, (2) its more reflexible ability to signal space distance variation. As examples, the results of some TCM code sequences on an AWGN channel and fading channels have been presented.

A class of signal waveforms for large scale Doppler frequency shift correction

In mobile satellite communication, Doppler frequency shift correction is one of the most important problems. This paper presents a new design method of signal waveforms for simplifying the estimation of the Doppler frequency shift. The proposed design method for transmission signal waveforms has three advantages: (1) an open loop technique is used for estimating the Doppler frequency shift at the receiving end; (2) the estimation of the Doppler frequency shift is simplified; and (3) the estimable range of the Doppler frequency shift exceeds the result presented by Simon and Divsalar (1989). If the transmission signal waveform belongs to the class of signal waveforms designed in this paper, the design of transmitter and receiver satisfy the matched criteria. Several examples of the design of transceivers are given by theoretical and numerical analysis.