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1. Modified IEEE 802.11 EDCF to Implement QoS of Multimedia Traffic | |||
Liqiang Zhao | |||
Electrics, Communication and Autocontrol Technology 05 September 2006 | |||
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Abstract:Enhanced distributed coordination function has been proposed in IEEE 802.11e draft to ensure QoS of multimedia traffic over WLAN. However the performance of EDCF may be poor in some cases. Thus, a modified EDCF, MEDCF is presented in this paper, which can supply different multiple access techniques to services with different requirements on QoS, such as p-persistent CSMA/CA for real-time service and non-persistent CSMA/CA for non-real-time service. Analysis and simulation show that MEDCF can support multimedia service and assure quality of real-time service. | |||
TO cite this article:Liqiang Zhao. Modified IEEE 802.11 EDCF to Implement QoS of Multimedia Traffic[OL].[ 5 September 2006] http://en.paper.edu.cn/en_releasepaper/content/8215 |
2. Adaptive Antenna System in IEEE 802.11 WLAN | |||
Liqiang Zhao | |||
Electrics, Communication and Autocontrol Technology 04 September 2006 | |||
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Abstract:Directional distributed coordination function (D-DCF), a modified medium access control protocol of IEEE 802.11, is proposed in this paper to support smart adaptive array antennas over WLAN. D-DCF based on hybrid virtual carrier sense (HVCS) mechanism can coexist with DCF. A smart antenna has omni-directional and directional mode in operation. In D-DCF, before sending any data-frames, the sender and receiver node transmit a pilot sequence by means of omni-directional request-to-send/clear-to-send (ORTS/OCTS) handshake mechanism. Based on the pilot, the directional beam can be formed by the smart antenna. Then the node can transmit its data-frame in directional mode. The other nodes save the transmission time between the sender and receiver in omni-directional mode in their network allocation vectors. When the sender and receiver communicate in directional mode, the other nodes can contend channel to send their data-frames. Hence, D-DCF supports space division multiple access (SDMA). Moreover, D-DCF supports both forward and backward transmission in one access period. Simulation results show that D-DCF can support smart antennas effectively and provide much higher network throughput, lower delay, jitter and packet-loss-rate than DCF does. | |||
TO cite this article:Liqiang Zhao. Adaptive Antenna System in IEEE 802.11 WLAN[OL].[ 4 September 2006] http://en.paper.edu.cn/en_releasepaper/content/8174 |
3. Performance analysis of IEEE 802.11 under an un-ideal channel | |||
Liqiang Zhao | |||
Electrics, Communication and Autocontrol Technology 31 August 2006 | |||
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Abstract:A simple analytical model for performance analysis of IEEE 802.11 WLAN under un-ideal condition is proposed in this paper. Simulation results show that the model is accurate to compute the saturation throughput, packet drop probability and delay under un-ideal channel. | |||
TO cite this article:Liqiang Zhao. Performance analysis of IEEE 802.11 under an un-ideal channel[OL].[31 August 2006] http://en.paper.edu.cn/en_releasepaper/content/8127 |
4. Performance Analysis of IEEE 802.11 Point Coordination Function | |||
Liqiang Zhao | |||
Electrics, Communication and Autocontrol Technology 21 August 2006 | |||
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Abstract:IEEE 802.11 includes two medium access control (MAC) protocols, a basic distributed coordination function and an optional point coordination function (PCF). PCF is a polling-based MAC protocol able to support collision free and time bounded services. However no suitable PCF analytical model is presented now. A simple, but extremely accurate, analytical model is presented in this paper to compute the system throughout. Simulation results show that the model is valid. | |||
TO cite this article:Liqiang Zhao. Performance Analysis of IEEE 802.11 Point Coordination Function[OL].[21 August 2006] http://en.paper.edu.cn/en_releasepaper/content/7978 |
5. A Multi-service Timeslot Dynamic Reservation Protocol for Multimedia over IEEE 802.11 Ad Hoc Wireless LAN | |||
Liqiang Zhao | |||
Electrics, Communication and Autocontrol Technology 18 August 2006 | |||
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Abstract:This paper presents a multi-service timeslot dynamic reservation (MTDR) protocol to support voice with constant bit-rate (CBR), video with variable bit-rate (VBR) and data with available bit-rate (ABR) over IEEE 802.11 Ad hoc wireless LAN. In MTDR, Real-time service (voice and video) has a higher priority assigned than non real-time service (data), in accessing the shared channel. The quality of real-time service can be guaranteed by reserving service timeslots. Moreover, MTDR defines multiple service timeslots respectively for CBR and VBR real-time services to meet their different requirement on quality of service (QoS). A suitable analytical approach is proposed in order to evaluate the voice, video and data subsystem performance. Simulations show that MTDR is able to provide almost 90% channel utilization, low call blocking probability due to setup time exceeded and packet loss due to delay expiry, and low jitter for real-time multimedia service. | |||
TO cite this article:Liqiang Zhao. A Multi-service Timeslot Dynamic Reservation Protocol for Multimedia over IEEE 802.11 Ad Hoc Wireless LAN[OL].[18 August 2006] http://en.paper.edu.cn/en_releasepaper/content/7969 |
6. Performance Analysis of MIMO-OC Systems with and without Co-channel Interference | |||
Yue Dianwu | |||
Electrics, Communication and Autocontrol Technology 12 June 2006 | |||
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Abstract:In this paper, we investigate performance of multiple-input /multiple-output (MIMO) systems employing optimum combining over spatial correlated Rayleigh fading channels with and without co-channel interference. Based on the theory of complex matrix variate distributions, we give a unified approach to the performance analysis for such MIMO systems, and derive exact closed-form expressions for the system outage probability, which are very general including some of existing related results as special cases and allowing for the correlated structures of both signal and interferers to be arbitrary at both transmitter and receiver ends. | |||
TO cite this article:Yue Dianwu . Performance Analysis of MIMO-OC Systems with and without Co-channel Interference[OL].[12 June 2006] http://en.paper.edu.cn/en_releasepaper/content/7084 |
7. A Novel Chaotic Shift Keying Communication Scheme with Frequency Analysis- based Methods | |||
Tang Binhua ,Yang Zhi | |||
Electrics, Communication and Autocontrol Technology 30 March 2006 | |||
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Abstract:A novel kind of CSK communication scheme is put forward in the paper, which adopts frequency analysis-based methods (FAM). At the transmitter, the original information bits are modulated with the Chen’s chaotic signals, and then transmitted via the wireless or cable channels, lastly at the receiver, the received modulated signals will be analyzed within the frequency domain. The information can easily be demodulated, with the decisions made from the different frequency domain distribution of the received modulated signals. The relevant analysis and experiments have both demonstrated the potential advantages of the proposed method in communication fields. | |||
TO cite this article:Tang Binhua ,Yang Zhi . A Novel Chaotic Shift Keying Communication Scheme with Frequency Analysis- based Methods[OL].[30 March 2006] http://en.paper.edu.cn/en_releasepaper/content/6000 |
8. A Novel Resource Allocation and Reservation Algorithm for IEEE 802.16 network | |||
Feng Chang’an ,Xu Fangmin ,Zhou Zheng | |||
Electrics, Communication and Autocontrol Technology 13 March 2006 | |||
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Abstract:Providing Quality of Service (QoS) guarantees for heterogeneous classes of traffic with different QoS requirements in fixed Broadband Wireless Access (BWA) system is a very important issue. Although IEEE 802.16d MAC protocol has been proposed to support QoS for various kinds of applications, there are still some key points undefined in the protocol, such as the resource allocation and bandwidth request algorithms etc. In this paper, we propose a new resource allocation algorithm for the IEEE 802.16d protocol and present a novel resource reservation scheme. Our algorithm provides QoS support to real-time traffic with high priority while maintaining bandwidth to low priority traffic. Analytical and simulation results illustrate our architecture. | |||
TO cite this article:Feng Chang’an ,Xu Fangmin ,Zhou Zheng . A Novel Resource Allocation and Reservation Algorithm for IEEE 802.16 network[OL].[13 March 2006] http://en.paper.edu.cn/en_releasepaper/content/5671 |
9. Modified Simulation of Path-number Distribution for Multi-Path Radio Propagation in Land High-Speed Locomotive Environment | |||
Zhang Sheng | |||
Electrics, Communication and Autocontrol Technology 13 March 2006 | |||
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Abstract:In this paper, a new simulation model are proposed for the path-number distribution for multi-path propagation in land high-speed locomotive environment. Markovian birth-and-death process is considered for the instantaneous path-number variation, involving the factor of speed. A path-number distribution for the multipath propagation in land high speed mobile communications is derived. Theoretical values of the present model agree well with experimental results. The dynamic variation of path number with the mobile station moving is simulated , and both the method and results are presented. This results show the speed is the most important variable, and the method in this paper is better than the other methods. | |||
TO cite this article:Zhang Sheng. Modified Simulation of Path-number Distribution for Multi-Path Radio Propagation in Land High-Speed Locomotive Environment[OL].[13 March 2006] http://en.paper.edu.cn/en_releasepaper/content/5667 |
10. UTILIZING CHANNEL STATE INFORMATION IN SC-FDE: AN OPTIMAL SIGNAL SUBSPACE APPROACH | |||
DU Yan,GONG Liang,LI Jianfei | |||
Electrics, Communication and Autocontrol Technology 13 February 2006 | |||
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Abstract:In this paper, we propose a new concept called optimal signal subspace, based on which we introduce a schematic approach of utilizing channel state information in SC-FDE system. We prove that the received signal-to-noise power ratio could achieve its maximum when the transmitted signals are represented by the basis of the optimal signal subspace. Although the spectrum used in this scheme is less than that in traditional SC-FDE systems, simulation results show that the new system has a comparable power and spectrum efficiency when the dimension of the optimal signal subspace is chosen properly. We also propose a criterion for determining the dimension of the optimal signal subspace, with which we can achieve the same bit error rate performance as Gaussian channel when signal transmitted through a multipath channel. | |||
TO cite this article:DU Yan,GONG Liang,LI Jianfei. UTILIZING CHANNEL STATE INFORMATION IN SC-FDE: AN OPTIMAL SIGNAL SUBSPACE APPROACH[OL].[13 February 2006] http://en.paper.edu.cn/en_releasepaper/content/5216 |
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