Wireless Network Research
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

Design PHY/MAC Cross-layer protocols for IEEE 802.11 and 802.16 WLAN and WMAN. PowerPoint PPT Presentation


  • 97 Views
  • Uploaded on
  • Presentation posted in: General

Wireless Network Research. 王蒞君教授. Explore the potential advantages of multi-user multi-input multi-output (MU-MIMO) systems from network aspect. Design the cross-layer network architecture for Cognitive Radio (CR) network.

Download Presentation

Design PHY/MAC Cross-layer protocols for IEEE 802.11 and 802.16 WLAN and WMAN.

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Wireless Network Research

王蒞君教授

Explore the potential advantages of multi-user multi-input multi-output (MU-MIMO) systems from network aspect.

Design the cross-layer network architecture for Cognitive Radio (CR) network.

Analyze the UWB systems under IEEE 802.15.3a/4a channel model with RAKE receiver.

UWB

MU-

MIMO

CR

WLAN/

WiMax

Mesh

Network

MC-DS

CDMA

Investigate Radio Resource Management Techniques of Multi-Carrier Direct Sequence Code Division Multiple Access (MC-DS-CDMA) and High Speed Downlink Packet Access (HSDPA).

Design PHY/MAC Cross-layer protocols for IEEE 802.11 and 802.16 WLAN and WMAN.

A scalable multi-channel ring-based Wireless Mesh Network (WMN) is proposed to optimize the tradeoff among delay, throughput, and coverage.

Wireless Network Lab, NCTU, Taiwan


Multi-Hop Cooperative Relay Network: Objective

  • Investigating the impacts of cooperative relay on handoff, capacity, and coverage from cooperative diversity and information mixing perspectives.

Wireless Network Lab, NCTU, Taiwan


Cooperative Diversity

  • Virtual antenna arrays.

  • Macro-diversity gain to combat shadowing.

  • Micro-diversity in the presence of fading.

Wireless Network Lab, NCTU, Taiwan


Information Mixing (Network Coding)

  • Traditional multi-hop relaying

    • Information exchange between A and B needs 4 transmissions.

  • Information mixing multi-hop relaying

    • Only 3 transmissions are needed.

Wireless Network Lab, NCTU, Taiwan


Multi-Hop Cooperative Relay Network: Subjects

  • Cooperative Diversity in Wireless Networks (偉賢)

  • Handoff in Relay-based WiMax networks with directional antennas (政敏)

  • Soft handoff in Relay-based WiMax networks (文山)

  • Capacity analysis in WiMax multi-hop relay networks (建華)

  • Network coding for cooperative relay network (tbd)

Wireless Network Lab, NCTU, Taiwan


Multi-Hop Cooperative Relay Network

  • Sponsor: MoE ATU Program

  • Contact: Jane-Hua Huang

  • Current Results:

    • Jane-Hwa Huang, Li-Chun Wang and Chung-Ju Chang, “Capacity and QoS for A Scalable Ring-based Wireless Mesh Network,” to appear in IEEE J. Select. Areas Commun., Special issue on wireless mesh network.

    • Jane-Hwa Huang, Li-Chun Wang and Chung-Ju Chang, “Wireless Mesh Networks for Intelligent Transportation Systems,” IEEE SMC 2006.

Wireless Network Lab, NCTU, Taiwan


Cognitive Radio

  • Overview:

    • A CR ad hoc network is a dynamically reconfigurable wireless network with no fixed infrastructure or central administration.

    • Nodes in these networks move arbitrary, and the radio spectrum which they occupy may change frequently.

  • Sponsor: NSC

  • Contact: Chung-Wei Wang

Wireless Network Lab, NCTU, Taiwan


Cognitive Radio - Subject

  • Clustering Architecture for CR Networks (中瑋)

  • Spectrum Opportunity Identification Technique for CR Systems

    • A Game Theoretic Framework for Interference Avoidance in cooperative CR networks (中瑋)

    • CR MAC for MIMO network (盈志)

    • Coexistence of ad hoc and infrastructure networks (銘賓)

  • Coverage and Capacity of Wireless CR Mesh Networks (建華)

  • Cross-layer Analysis for Multicasting Information in CR Networks (tbd)

Wireless Network Lab, NCTU, Taiwan


Spectrum Opportunity Identification Technique for CR Systems

  • One fundamental issue for the CR system is how to rapidly establish a temporary communication link on the spectrum of the exiting users.

  • We investigate the feasibility issue of establishing both an infrastructure-based link and an ad hoc link using the same spectrum simultaneously in an overlapped area.

Wireless Network Lab, NCTU, Taiwan


CR Network

Cluster Relay

Clustering Architecture for CR Networks

  • In a building, CR devices self-organize into several cluster networks.

  • We proposed cluster head election and member assignment algorithms to form clusters.

Wireless Network Lab, NCTU, Taiwan


Coverage and Capacity of Wireless CR Mesh Networks

  • We propose a scalable multi-channel multi-hop wireless mesh network.

  • Without the legacy IEEE 802.11 MAC protocol, a simple frequency planning is applied to effectively utilize the available multiple channels.

  • An optimization problem is formulated to maximize the coverage and capacity subject to the QoS requirement.

Wireless Network Lab, NCTU, Taiwan


Cross-layer Analysis for Multicasting Information in CR Networks

  • Multicasting is a more efficient way of supporting group communications than unicasting or broadcasting.

  • We want to establish a scalable and efficient multicast routing algorithm that is suitable for a CR ad hoc network.

Wireless Network Lab, NCTU, Taiwan


Current Results:

  • [1] Li-Chun Wang, Chung-Wei Wang, and Chuan-Ming Liu, “Adaptive Contention Window-based Cluster Head Election Algorithms for Wireless Sensor Networks,” VTC'05 Fall, vol. 3, pp. 1819-1823, September 2005.

  • [2] Li-Chun Wang, and Anderson Chen, “On the Coexistence of Infrastructure-Based and Ad Hoc Connections for a Cognitive Radio System,” to be appeared in CrownCom 2006.

Wireless Network Lab, NCTU, Taiwan


MIMO-UWB (1/2)

  • Objective: Performance analysis of the MB-OFDM MIMO-UWB system

  • Subject:

    • BER analysis and system design under the IEEE 802.15.4a UWB channel model using MB-OFDM and MIMO techniques

  • Sponsor: NSC

  • Contact: Wei-Cheng Liu

Wireless Network Lab, NCTU, Taiwan


MIMO-UWB (2/2)

  • Current Results:

    • Li-Chun Wang and Wei-Cheng Liu, “Performance of Pulse Position Modulated Signals over the Ultra-Wideband Channel with Multiple Transmit and Receive Antennas,” IEEE Vehicular Technology Conference 2004 Fall, vol. 2, pp. 822-826, Sep. 26-29, 2004.

    • Li-Chun Wang, Wei-Cheng Liu, and Kuan-Jiin Shieh, “On the Performance of Using Multiple Transmit and Receive Antennas in Pulse Based Ultra-Wideband Systems,” IEEE Transactions on Wireless Communications, vol. 4, no. 6, pp. 2738-2750, Nov. 2005.

    • Wei-Cheng Liu and Li-Chun Wang, “Performance Analysis of Pulse Based Ultra-Wideband Systems in the Highly Frequency Selective Fading Channel with Cluster Property,” appeared in VTC2006-Spring.

    • Wei-Cheng Liu and Li-Chun Wang, “Performance Analysis of Pulse Based Ultra-Wideband Systems in the Highly Frequency Selective Fading Channel with Random Clusters and Rays,” submitted to IEEE Trans. Veh. Technol.

    • Wei-Cheng Liu and Li-Chun Wang, “BER Analysis of the IEEE 802.15.4a Channel Model with RAKE Receiver,” accepted by VTC2006-Fall.

Wireless Network Lab, NCTU, Taiwan


Scheduling for MIMO OFDM (1/2)

  • Objective:

  • Subject:

    • Link reliability and coverage enhancement for multiplexing-based MIMO OFDMA systems by scheduling. (正偉)

    • Performance analysis of the zero-forcing beamforming for MIMO broadcast channel systems. (俥榮, Now)

    • Space-time scheduling for MIMO BC systems with co-channel interference.

      (俥榮, Next)

    • Space-time-frequency scheduling for MIMO-OFDM

Wireless Network Lab, NCTU, Taiwan


Scheduling for MIMO OFDM (2/2)

  • Sponsor: NSC 2007~2010?

  • Contact: Chu-Jung Yeh

  • Current Results:

    • Comparison of transmit and receive zero-forcing scheduler for MIMO broadcast channels

    • Analyze the link outage and cell coverage for multiplexing-based MIMO OFDM systems.

Wireless Network Lab, NCTU, Taiwan


Handoff in OFDMA-based Network

  • Objective:

    • MAC design and performance analysis for OFDMA-based inter/intra network handoff

  • Subject:

    • Enhanced MAC layer hard handoff for mobile WiMax (銘賓)

    • Soft handoff for mobile WiMax with relay station (文山)

    • Smart vertical handoff between WiFi and WiMax (鴻昕)

  • Sponsor:

  • Contact: Anderson Chen

Wireless Network Lab, NCTU, Taiwan


Motivation

  • OFDMA PHY is considered a candidate access technique for the future wireless system to combat the severe multipath fading.

  • However, the future mobile terminal may equip multiple wireless interfaces to connect various wireless networks, e.g WiFi/WiMax.

Wireless Network Lab, NCTU, Taiwan


Issues

  • Always best connect (ABC) becomes an important issue for the handoff in heterogeneous network.

    • Seamless handoff is one of the key issue for the ABC in the inter/intra network handoff.

  • Sub-channel allocation for the HHO/SHO/FBSS in OFDMA-based system is another challenging issue.

    • Which sub-channels should be reserved for the handoff MNs to increase the transmission success probability and thus expedite the re-entry process?

Wireless Network Lab, NCTU, Taiwan


Current Results

  • Li-Chun Wang, Hung-Hsi Chen, Anderson Chen, Chung-Ju Chang, “Optimal channel search time for handoff in the IEEE 802.11 WLANs,” appeared in VTC 2006 Spring

  • Anderson Chen and Li-Chun Wang, “On the performance of re-entry process in OFDMA-based IEEE 802.16 WiMax,” to be appeared in WPMC 2006

Wireless Network Lab, NCTU, Taiwan


  • Login