Suboptimal Partial Transmit Sequence-Active Interference Cancellation with Particle Swarm Optimization
- PDF / 1,202,156 Bytes
- 9 Pages / 600.05 x 792 pts Page_size
- 0 Downloads / 192 Views
Research Article Suboptimal Partial Transmit Sequence-Active Interference Cancellation with Particle Swarm Optimization Poramate Tarasak, Zhiwei Lin, Xiaoming Peng, and Francois Chin Department of Modulation and Coding, Institute for Infocomm Research, Agency for Science Technology and Research, 1 Fusionopolis Way, no. 21-01 Connexis, Singapore 138632 Correspondence should be addressed to Poramate Tarasak, [email protected] Received 31 December 2009; Revised 16 June 2010; Accepted 11 August 2010 Academic Editor: Chi Ko Copyright © 2010 Poramate Tarasak et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Active interference cancellation (AIC) is an effective technique to provide interference avoidance feature for an ultrawideband (UWB) OFDM transmitter. Partial transmit sequence-AIC (PTS-AIC), which was recently proposed as an improvement of AIC, requires high computational complexity by doing the exhaustive search of all possible weighting factors whose number grows exponentially with the number of subblocks used. To reduce the complexity of PTS-AIC, this paper proposes a suboptimal way, called particle swarm optimization (PSO), to choose the weighting factors suboptimally without much performance degradation. Both continuous and discrete versions of PSO have been evaluated, and it has been shown that the discrete PSO is able to reduce the complexity significantly without sacrificing the performance of PTS-AIC in many cases.
1. Introduction Ultrawideband (UWB) communication, a spectrum underlay system, has a very small power spectral density that spans over hundreds of megahertz. While a UWB device must endure interference from the primary narrowband devices, the UWB transmission must not cause interference back to them. There are several works studying the impact of interference if the UWB system is to coexist with other narrowband systems, for example, [1–4]. These studies indicate performance degradation as a result of mutual interference between UWB and narrowband systems. Due to the secondary nature of UWB devices, it is their requirement to avoid causing the interference in the first place. One approach is to enhance the UWB device with the “detect-and-avoid” (DAA) [5] capability, sensing any ongoing narrowband transmissions and intelligently keeping away from the overlapped spectrum. If the narrowband transmission is found, the UWB device will adjust its transmission such that the effect of the UWB transmission will be negligible at the primary device receiver. DAA has been an interesting research topic on UWB recently. The
strong interest of DAA is attributed to widespread usage of wireless applications sharing the same or overlapped part of the spectrum band. For example, current important narrowband systems that share parts of the UWB spectrum are WiMAX at the 3.5 GHz frequency range and IEEE802.11a at the 5 GHz frequency range.
Data Loading...
