Green Multi-users CoMP Transmission Technique

Visiting researcher: Prof. Xiaofeng Tao (BUPT)
Host researcher: Prof. Harald Hass (UoE)
Duration: 2 months
Status: Ongoing
 

Biography of the visiting researcher

Dr. TAO, Xiaofeng, Professor of Beijing University of Posts and Telecommunications, visiting professor of Stanford University, vice Director of Key Laboratory of Universal Wireless Communications (Ministry of Education) , Member of Consultative Committee on UN Information Technology (CCIT), China Association for Science and Technology(CAST). As one of the two chief architects of the Chinese national 4G (4th generation) wireless communication system, supported by the Chinese Ministry of Science and Technology (MOST), he led the Chinese 4G TDD working group comprising of four Chinese best universities, and established a cellular trial network adopted by the Chinese national 4G program in 2006. He is the inventor or co-inventor of 50 patents, the author or co-author of 120 papers, in wireless communication areas. He is a winner of 2008 Chinese National Award for Technological Invention (second price).
 

Background and Motivation

Cooperative MIMO aims to utilize distributed antennas on multiple radio devices to achieve benefits similar to those provided by conventional MIMO systems. The envisaged advantages of cooperative MIMO are the capability to improve system capacity, cell edge user throughput (and thus fairness), and coverage. Three types of cooperative MIMO schemes have been proposed for cellular systems: coordinated multipoint transmission (CoMP), fixed relay, and mobile relay. The Third Generation Partnership Project (3GPP) is currently evaluating CoMP technologies for its fourth-generation (4G) cellular communication standard, Long Term Evolution-Advanced (LTE-Advanced).
 
CoMP is an emerging technique to combat inter-cell interference and to improve cell edge performance. The idea is to share data and channel state information (CSI) among neighboring base stations (BSs) to coordinate their transmissions in the downlink and jointly process the received signals in the uplink. CoMP techniques can effectively turn otherwise harmful inter-cell interference into useful signals, allowing significant power gain, channel rank advantage, and/or diversity gains to be exploited.
 
The disadvantages of CoMP come from the increased system complexity and the large signaling overhead required for supporting cooperation. As a consequence, it increases the total transmission power by introducing multiple transmitting points and this extra power consumption is significant in the case of a large number of CoMP users in the network. Significant research is required to solve these problems, and this exchange proposal is to bring together the expertise of two institutes who have a proven record on MIMO and interference mitigation techniques for wireless systems.
 
While under ideal conditions, CoMP is a strong candidate to mitigate co-channel interference and to enhance the cell-edge throughput in a wireless network, the key problem of CoMP is the required signaling and channel estimation overhead. This overhead significantly compromises system spectral efficiency and power efficiency. The latter aspect has gained importance recently due the requirement reduced energy consumption in these networks. Therefore, the aim of the proposed research is study methods to reduce the control signaling overhead in CoMP networks with particular focus on energy reduction.
 

Research Activities

  1. The co-researchers will update each other on their existing CoMP work in a one-day seminar (e.g., busy burst and spatial modulation work at Edinburgh University).
  2. We will study and evaluate possible strategies to mitigate the signaling overhead in existing CoMP transmission systems
  3. We will develop a general framework to assess the energy efficiency of existing CoMP transmission schemes and will look into power control techniques to improve energy consumption.
  4. We will assess the performance of the new low overhead and low energy CoMP systems in terms of their ability to maintain high and robust cell edge user throughput. This will involve an investigation into user scheduling strategies to accommodate the new methods for channel estimation and power control.
 

Outcomes

To be updated.
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