Intercarrier Interference Self-Cancellation Space-Frequency Codes for MIMO-OFDM

Abstract

Abstract-Space-frequency (SF) codes that exploit both spatial and frequency diversity can be designed using orthogonal frequency division multiplexing (OFDM). However, OFDM is sensitive to frequency offset (FO), which generates intercarrier interference (ICI) among subcarriers. We investigate the pair-wise error probability (PEP) performance of SF codes over quasistatic, frequency selective Rayleigh fading channels with FO. We prove that the conventional SF code design criteria remain valid. The negligible performance loss for small FOs (less than 1%), however, increases with FO and with signal to noise ratio (SNR). While diversity can be used to mitigate ICI, as FO increases, the PEP does not rapidly decay with SNR. Therefore, we propose a new class of SF codes called ICI self-cancellation SF (ISC-SF) codes to combat ICI effectively even with high FO (10%). ISC-SF codes are constructed from existing full diversity space-time codes. Importantly, our code design provide a satisfactory tradeoff among error correction ability, ICI reduction and spectral efficiency. Furthermore, we demonstrate that ISC-SF codes can also mitigate the ICI caused by phase noise and time varying channels. Simulation results affirm the theoretical analysis.Index Terms-Inter-carrier interference (ICI), multiple input multiple output (MIMO), orthogonal frequency division multiplexing (OFDM), space-frequency (SF) codes.

Downlink Linear Precoders Based on Statistical CSI for Multicell MIMO-OFDM

“…The case without ICI is then a special case of this scenario. The ICI occurs when there is carrier frequency offset due to synchronization errors and Doppler shifts [1,38,43]. This leads to loss of orthogonality among subcarriers which introduces more interference to the system.…”

“…Both MIMO and OFDM are known to facilitate the wireless networks with excellent capabilities; when MIMO and OFDM are combined together, MIMO-OFDM achieves tremendous capacities that will be enjoyed by 5G systems in the near future. While MIMO-OFDM systems have superb performance, several challenges invoked by MIMO and OFDM characteristics are involved in the system design [1][2][3][4][5][6]. Other competing technologies in 5G networks are filtered-OFDM (F-OFDM) and universal filtered multicarrier (UFMC) that are receiving attention in the literature [7,8].…”

“…We shall extend this methodology to the problem of downlink multiuser multicell MIMO-OFDM linear precoder design with statistical CSI. Considering the downlink leads to a somewhat different power constraint compared to the uplink, and the OFDM assumption gives rise to concepts such as frequency selectivity [17,30,31], channel tap correlations [17,[31][32][33][34], and intercarrier interference (ICI) [1,[35][36][37][38], all of which must be taken into account in the precoder design. Our derivation of statistical precoding for the downlink multicell MIMO-OFDM system is a unification of previous works [20,29], and while several details are different from these two works, this derivation is not the main contribution.…”

“…We study the effects of tap correlation on the precoder design and system performance. Next, we allow ICI among OFDM subcarriers which is caused by carrier frequency offset due to synchronization errors and Doppler shifts [1]. The ICI introduces a new source of interference in addition to the intercell and intracell interference.…”

ICI Canceling Space-Frequency Block Code for MISO-OFDM in Fast Fading Channels

“…It does not sacrifice spectral efficiency, but often needs a maximum-likelihood sequence estimator (MLSE) at the receiver to minimize the bit-error-rate (BER) performance loss and this increases the receiver complexity significantly. Recently, ICI canceling techniques for multipleinput multiple-output (MIMO) systems have been investigated: in [17], the space-frequency (SF) coding for MIMO-OFDM is combined with the frequency-domain ICI self-cancelation technique in [8], and in [18], the frequency-domain PRC [12] is employed for an OFDM-based spatial multiplexing system. These methods can provide either diversity and coding gains or a throughput gain in addition to the ICI cancelation ability.…”