ZTE Communications ›› 2015, Vol. 13 ›› Issue (1): 43-49.doi: 10.3969/j.issn.1673-5188.2015.01.006

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Interference-Cancellation Scheme for Multilayer Cellular Systems

Wei Li1, Yue Zhang1, Li-Ke Huang2   

  1. 1. University of Bedfordshire, Luton, LU1 3JU, UK;
    2. Aeroflex UK, Stevenage, SG1 2AN, UK
  • Received:2014-09-18 Online:2015-03-25 Published:2015-03-25
  • About author:Wei Li (wei.li@beds.ac.uk) received his BEng degree from the University of Electronic Science and Technology of China in 2010. He is currently working towards his PhD degree at the University of Bedfordshire, UK, and working with Aeroflex UK on a project looking at the baseband signal process problem in LTE networks. His research interests include signal processing for mobile communications, cognitive radio, OFDM channel estimation, and cooperative communications via relays.
    Yue Zhang (yue.zhang@beds.ac.uk) is currently senior lecturer in the Department of Computer Science and Technology, University of Bedfordshire. He is also on industry secondment from the Royal Academy of Engineering working with Aeroflex UK on a high-throughput wireless measurement platform project. He obtained his BEng and MEng degrees from Beijing University of Post and Telecommunications in 2001 and 2004. He received his PhD degree from Brunel University, UK, in 2008. He has worked as a research engineer for the EU IST FP6 project called PLUTO. He then worked as a signal processing design engineer at Anritsu. He was responsible for RF/IF, digital, and DSP design for various wireless communication systems. His research interests include signal processing, wireless communications systems, MIMO-OFDM systems, radio propagation model, and multimedia and wireless networks. He is a member of IEEE and IET.
    Li-Ke Huang (li-ke.huang@aeroflex.com) is a technical and research manager at Aeroflex UK. He develops testing and measurement technologies for wireless systems. He specializes in transceiver algorithms and architecture designs for all major wireless communication standards. He is responsible for products and technologies R&D. His research interests include communication system designs and signal processing algorithms and architectures. He received his BSc degree in electronic engineering at Shenzhen University, China, in 1998. He received his PhD degree in communication and signal processing from Imperial College London in 2003.

Abstract: A 5G network must be heterogeneous and support the co-existence of multilayer cells, multiple standards, and multiple application systems. This greatly improves link performance and increases link capacity. A network with co-existing macro and pico cells can alleviate traffic congestion caused by multicast or unicast subscribers, help satisfy huge traffic demands, and further extend converge. In order to practically implement advanced 5G technology, a number of technical problems have to be solved, one of which is inter-cell interference. A method called Almost Blank Subframe (ABS) has been proposed to mitigate interference; however, the reference signal in ABS still causes interference. This paper describes how interference can be cancelled by using the information in the ABS. First, the interference-signal model, which takes into account channel effect, time and frequency error, is presented. Then, an interference-cancellation scheme based on this model is studied. The timing and carrier frequency offset of the interference signal is compensated. Afterwards, the reference signal of the interfering cell is generated locally and the channel response is estimated using channel statistics. Then, the interference signal is reconstructed according to previous estimation of channel, timing, and carrier frequency offset. The interference is mitigated by subtracting the estimated interference signal. Computer simulation shows that this interference-cancellation algorithm significantly improves performance under different channel conditions.

Key words: 5G, cell edge interference, almost-blank subframe, eICIC