Spectrally efficient frequency division multiplexing (SEFDM) has been recognised as a promising multi‐carrier technology since it can offer a higher spectral efficiency than orthogonal frequency division multiplexing (OFDM). In this study, the authors provide a framework for SEFDM transceiver design and investigate the techniques of channel equalisation and data detection of SEFDM over frequency selective fading scenarios. Specifically, they first demonstrate through mathematical analysis that SEFDM with the proposed frequency‐domain equalisation scheme can benefit from the frequency diversity, and thus, performs more robust to the frequency selective fading environment than OFDM. To effectively mitigate inter‐carrier interference raised by the non‐orthogonality between sub‐carriers of SEFDM, they then propose a low‐computational data detection scheme based on the Viterbi principle and maximum a posteriori criterion. The proposed detector can provide an indistinguishable performance from the maximum likelihood detection using sphere decoding while entailing a much lower computation. Numerical results validate the superiority of SEFDM to OFDM over frequency selective fading channels.

This paper reveals that nonlinear propagation is a critical problem for the long term evolution (LTE) technology based on the radio-over-fibre (RoF) system. Therefore, a direct modulation based frequency dithering (DMFD) method is proposed for nonlinear propagation compensation, namely the self phase modulation (SPM) and stimulated brillouin scattering (SBS). We found that DMFD method operates substantially different in RoF systems. The major difference is that DMFD signal frequency fdhas to be much smaller than the RoF carrier frequency fRF; thus the condition of {fdRF} has to be stringently obeyed. Analysis of the optical launch power (OLP) with DMFD method reveals that the SBS threshold is above ~6 dBm for LTE-RoF system. In addition, we also unfold that DMFD method does not induce an additional distortion for the linear and optimum OLP regions, which are frequency chirp dependent. Hence the proposed method improves the LTE-RoF system without any shortcoming. Finally, at OLP values of 8 dBm and 10 dBm, LTE-RoF system exhibits an average error vector magnitude (EVM) improvement of ~4.32% and ~6.18%, respectively, for the 50 km transmission span.

Relay nodes (RN) are used as an important structure to extend the coverage of the Third Generation Partnership Program's Long Term Evolution (3GPP-LTE). The promising technology as the interface between eNodeB (eNB) and RN is radio-over-fibre (RoF), due to its longer span transmission capability. In this paper, we propose an alternative technique to 2×2 multiple-input and multiple-output (MIMO) in LTE structure for transmission over 60 km directly modulated RoF link by introducing frequency division multiplexing (FDM) for orthogonal FDM (OFDM). The system is demonstrated theoretically and experimentally. In the baseband, quadrature phase shift keying (QPSK), 16-quadrature amplitude modulation (QAM) and 64-QAM are considered as the single carrier modulations (SCM) according to the LTE standard. The system degradation pattern is identical between the theoretical and experimental system, thus proving the accuracy of the theoretical system design. The real time QPSK, 16-QAM and 64-QAM system achieved an average EVM of 5.84%, 5.90% and 5.97%, respectively for 2GHz and 2.6 GHz bands. These resultant EVMs are below the 8% 3GPP-LTE EVM requirement.

A simple and powerful modelling method in the time domain is established to resolve travelling waves inside photonic devices. The basic idea is to transform usual space–time coordinates (z, t) into a mixed grid (u, v) in which waves propagate along their characteristic lines, resulting in an inherent numerical stability, as well as easy interpretation of all parametric variables and their derivatives. In this study, the authors will demonstrate, for the first time, how the effect of gain dispersion can be dealt with using an efficient fourth-order algorithm, which attains high precision, high speed as well as very large stepsize. Excellent agreement with existing analytical results is obtained.

Pilot insertion for channel estimation in orthogonal frequency division multiplexing (OFDM) is a promising technique for broadband/high data rate wireless communications. In indoor diffuse optical wireless links, channel impulse response depends on the location of the receiver. For links to offer mobility tracking is essential which can be complex to implement. In this paper we propose channel estimation to allow receiver mobility. We have examined channel estimation with different interpolation methods for OFDM system and have compared the symbol error rates (SER) performance.

A simplified parallel step-by-step decoding algorithm is proposed for decoding Reed-Solomon (RS) codes. It uses new method to calculate the determinants of the temporarily changed syndrome matrices, based on the property of these matrices determined in this paper. By using the proposed method, the calculations of the determinants of the temporarily changed syndrome matrices become much simpler and thus the computational complexity of the step-by-step decoding algorithm is significantly reduced.

A limited-wavelength-interchangeable cross-connect (L-WIXC) is considered in this paper. While a (fully) wavelength-interchangeable cross-connect (WIXC) is functionally equivalent to a conventional switching matrix, the modeling of L-WIXC will differ from that of WIXC due to limitations in the wavelength interchange capability. We propose an analytical model for describing the connection setup in various L-WIXCs. Two methods for evaluating the blocking performances of L-WIXCs based on this model are introduced and applied for the analysis of four classes of L-WIXC.