Iterative channel estimation for multiuser fibre-wireless uplink exploiting semi-correlated ternary signals

作者：Ng Yin Hoe^*; Tan Ai Hui; Chuah Teong Chee

来源：IET Signal Processing, 2016, 10(4): 395-403.

DOI：10.1049/iet-spr.2015.0419

• channel estimation
• optical fibre networks
• computational complexity
• multi-access systems
• interference (signal)
• iterative channel estimation
• multiuser fibre-wireless uplink
• semicorrelated ternary signals
• multiuser fibre-wireless
• Fi-Wi uplink channels
• semi-correlated ternary pseudo-random signal
• iterative channel estimator
• computational complexity
• multiple access interference

A novel design of ternary signal sets is proposed for estimation of multiuser fibre-wireless (Fi-Wi) uplink channels. The design overcomes the current limitation in the maximum number of users that the system can accommodate by separating the signals in a set into subsets. The signals are uncorrelated between subsets, but correlated within subsets, thus forming a semi-correlated ternary pseudo-random signal (SC-TPRS) set. An iterative channel estimator based on the SC-TPRS scheme is then proposed for joint estimation of the Fi-Wi uplink channel. The computational complexity associated with the existing and the proposed estimators is derived and it is shown that the latter incurs substantially lower computational cost than the former. Numerical results show that despite using signals which are a few hundred times shorter, the proposed scheme can improve estimation accuracy dramatically over the existing scheme at low signal-to-noise ratios. The proposed scheme has a further advantage of allowing the designer to optimise the Fi-Wi system under the constraint of maximum permissible level of multiple access interference, since the amount of interference can be tuned by adjusting the number and size of the ternary signal subsets.

• 出版日期2016-6