Institute of Communications Engineering

Nanjing, China

Institute of Communications Engineering

Nanjing, China
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Zhang D.,Institute of Communications Engineering | Xu Y.,Shanghai JiaoTong University
IEEE Transactions on Vehicular Technology | Year: 2014

The average symbol-error-rate (SER) performances for the three-phase two-way relaying (TWR) protocols are analyzed and compared in Rayleigh fading channels, where the terminals and relay are interfered with by a finite number of cochannel interferers. The relay is assumed to operate in the decode-and-forward (DF) mode. Three TWR protocols where the terminals adopt different combining methods on the received signals from a relay link and a direct link are considered, and the tight approximate expressions of average SERs for these protocols are theoretically derived. Based on the analytic results, the SER performances of the three TWR protocols are compared in the interference-limited scenario. The results show that the TWR protocol where the terminals employ selection combining on the received signals from the relay and direct links can achieve good tradeoff between the average SER performance and computational complexity at the terminals. Moreover, we show that the three-phase TWR protocol outperforms the two-phase TWR protocol significantly in SER performance. © 1967-2012 IEEE.

Li Y.,Institute of Communications Engineering | He M.,Institute of command automation | Han Y.,NUDT
International Journal of Digital Content Technology and its Applications | Year: 2011

A game-theoretic framework was used to study the effect of modulation on the energy efficiency of cognitive CDMA (Code Division Multiple Access) communications for adaptive modulation. We designed an adaptive utility function which can link modulation, rate and power control. Since users are selfish and rational, a non-cooperative game was proposed, in which each user chose transmit power, transmit symbol rate as well as the modulation in order to maximize its own utility. Compared with a similar approach, our proposed algorithm can improve performance significantly.

Wang H.,Institute of Communications Engineering | Zhao H.,Zhengzhou University of Light Industry
IEEE International Symposium on Phased Array Systems and Technology | Year: 2010

Error vector magnitude (EVM) is extensively applied as a measure of wireless communication systems' performance. In this paper, the effects of amplitude and phase errors for satellite digital beam-forming (DBF) multi-beam phased array antenna systems on EVM are investigated. The analytic expression for EVM about array channels' amplitude and phase errors is derived and verified by computer simulation. © 2010 IEEE.

Liang T.,Nanjing Institute of Technology | Zhang Y.J.,Institute of Communications Engineering | Yuan G.B.,Institute of Communications Engineering | Guo L.,Nanjing Institute of Technology
Applied Mechanics and Materials | Year: 2014

In this paper, We propose a effective method which joint transmit antenna selection (TAS) and artificial noise to promote communication security in MIMO wiretap channels. Firstly, based on TAS protocol, the transmitter selects one antenna (the max-antenna) that maximizes the instantaneous signal-noise-ratio (SNR) at the receiver. Secondly, the transmitter uses the max-antenna to transmit valid data, and simultaneously, uses the remaining antennas to transmit artificial noise which only affects the eavesdropper. Thirdly, The receiver and the eavesdropper employ maximal-ratio combining (MRC) to combine the received signals. We focus on the practical scenario where the transmitter does not have any channel state information (CSI) of the eavesdropper's channel. Our joint TAS and artificial noise scheme (TAS-AN) have low complexity, and can enhance the system's security. The numerical simulation results verify our analysis. © (2014) Trans Tech Publications, Switzerland.

Tao Z.,Institute of Communications Engineering | Xiong-Wei Z.,PLA University of Science and Technology
Przeglad Elektrotechniczny | Year: 2011

Based on research of frame distortion estimation, an extraction priority assignment method is proposed for the MGS bit-stream. Firstly, extraction priority is derived from rate distortion optimization method. Then, frame distortion estimation is performed from estimation of coefficients dropping distortion and drift distortion. At last, depending on quality layer concept, extraction priorities are assigned efficiently. Experimental results show that the proposed method outperforms the priority assignment method and bit-stream extraction of H.264/SVC.

Zhu T.,Institute of Communications Engineering | Zhang X.-W.,PLA University of Science and Technology
Przeglad Elektrotechniczny | Year: 2011

This paper presents a rate control scheme for spatial scalability of H.264/SVC. At first, an adaptive method is proposed to decide the initial quantization parameter. Then, based on the transform coefficients distribution of spatial scalability, a new natural logarithm domain rate-distortion model is derived from the inspiration of the Cauchy-Density-Based model. Next, with above method and model, a rate control scheme is developed to match the characteristic of spatial scalability. The excellent performance of the proposed scheme is demonstrated by experimental results.

Yang W.,Institute of Communications Engineering | Cai Y.,Institute of Communications Engineering | Xu X.,Institute of Communications Engineering
Electronics Letters | Year: 2012

The performance of dual-hop MIMO amplify-and-forward relaying systems over an interference-limited Nakagami-m fading environment is investigated. Specifically, assuming the presence of multiple Nakagami-m faded co-channel interferers at the relay and a noisy destination, the closed-form expression for the outage probability is derived. Simulation results are presented to demonstrate the validity of the theoretical analysis. © 2012 The Institution of Engineering and Technology.

Zhan G.,Institute of Communications Engineering
2011 International Conference on Management Science and Industrial Engineering, MSIE 2011 | Year: 2011

Spectrum sensing is one of core technologies in cognitive radio. It can adapt to complicated electric-magnetic environments. By detecting environments in real time and extracting interference characteristic in frequency spectrum, it can use flexible spectrum assign strategy for adaptive communications. Spectrum sensing technology is discussed in this article. Then the realization scheme is proposed and applied in frequency-hopping communication systems. Computer simulations show that it can exactly provide spectrum occupation in real time for frequency-hopping communication systems. ©2011 IEEE.

Zhang T.,Institute of Communications Engineering | Cai Y.,Institute of Communications Engineering | Yang W.,Institute of Communications Engineering
Electronics Letters | Year: 2013

The performance of multi-source multi-relay wireless networks based on a joint source-relay-selection scheme is investigated over Rayleigh interference-limited fading channels. The tight lower bound and asymptotic expressions for the outage probability are derived and the diversity order of the system with/without co-channel interference is further discussed. Simulation results are presented to demonstrate the validity of the theoretical analysis. © The Institution of Engineering and Technology 2013.

Zhong W.,Institute of Communications Engineering
Proceedings - 2013 Wireless and Optical Communications Conference, WOCC 2013 | Year: 2013

In this paper, we study the optimal spectrum access in cognitive relay networks where multiple secondary users can access the unutilized idle spectrum of the primary users and conduct bidirectional communication. The spectrum access problem in the considered system model is defined as joint relay selection and discrete power control. Our goal is to maximize network utility function which takes the sum rate and the power consumption into account. We propose a decentralized synchronous update algorithm to obtain the optimal solution rather than the high complicated exhaustive search algorithm. In our proposed algorithm, we design a new objective function which consists of the network utility function and the penalty functions. Our designed objective function can guarantee the feasibility of the solution without knowing the infeasible strategy profiles in advance under mild conditions. It is proved that our proposed algorithm can converge to the optimal solution in finite steps. Simulation results verify our theoretic analysis. © 2013 IEEE.

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