An Experimental Investigation of Enhanced SM-OFDM Over Indoor Rician Multipath Channels

Abstract

In this letter, we investigate enhanced spatial modulation (ESM) aided orthogonal frequency division multiplexing (OFDM) systems. ESM extends the conventional SM by introducing a series of signal constellations. Existing research shows that ESM displays performance superiority over SM in flat-fading channels. For frequency-selective fading channels, we design a practical implementation of an ESM&SM aided OFDM hybrid system to characterize the bit error rate (BER) performance of ESM and conventional SM with an experimental wireless testbed. Form the experimental results, it is found that ESM achieves better BER performance than SM on frequency-selective channels, which are consistent with the Monte Carlo simulation results. Index Terms-Bit error rate (BER), enhanced spatial modulation (ESM), multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM), wireless testbed. I. INTRODUCTION M ULTIPLE-INPUT multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) [1] is a key enabling technique for modern high-rate communications. However, due to the use of multiple-antenna and multiplecarrier, current MIMO-OFDM suffers from several problems, such as the inter-channel interference (ICI), the inter-antenna interference (IAI), the need for multiple radio frequency (RF) chains [2], and the high peak-to-average power ratio (PAPR) of the transmitted signals. These problems result in extra complexity or power burden to MIMO-OFDM system design. Recently, spatial modulation-OFDM (SM-OFDM) has been proposed to address some of the above mentioned problems pertinent to MIMO-OFDM. The main idea of SM-OFDM is that at each channel use only one single transmit antenna (TA) activates its subcarrier for data transmission. The sparsity of the transmit vectors in frequency domain helps lower the PAPR, reduce the ICI, and allow a low-complexity receiver [2]-[4]. To date, some intensive studies have been conducted on SM-OFDM [5]-[7]. To be specific, [5] studied the average bit error rate (BER) performance of SM-OFDM with the socalled N-continuous (NC) precoder under perfect and imperfect channel estimations. [6] proposed a detection scheme for SM-OFDM which can effectively mitigate the effect of

Performance Analysis of Non-Ideal Sectorized SFR Cellular Systems in Rician Fading Channels With Unbalanced Diversity

“…Specifically, √ 3R/2 is the radius of the circle inscribed in the hexagon, that is, its apothem. In this figure 4 , ℘ 3 (θ) is the line segment connecting BS B 3 and the line 1 . The segment length is a function of θ.…”

“…These angles can be found from the slopes of lines 3 and 4 , respectively. In order to determine these slopes, the intersection points of the circumference C 3 4 The subscript 3 in ℘ and in the other variables refers to co-cell 3.…”

“…Fig. 16 shows the BER as a function of P c for both inner and outer regions of the sector of interest, parameterized by the antenna radiation pattern, for E b /N 0 = 30 dB, 64-QAM and K = [2, 4,6,8], that is, the diversity order is 4.…”

“…One parameter that features Rician fading is the ratio of the power contributions between the stronger path and the remaining multipaths and is named as K factor [3]. In [4], the BER of orthogonal-frequency-division multiple access (OFDMA) was evaluated for Rician fading via simulations. In [5], a scenario with co-channel interference was analyzed using the Chernoff bound to obtain BER expressions for binary modulations, which are accurate only in the low signal-to-noiseratio (SNR) region.…”

Experimental Analysis of Spatial Modulation Systems in Mixed LOS/NLOS Scenarios

“…The following implementations [4], [24] have made up for this lack but the propagation environment is a simple LOS channel. In the recent two years, authors of [25] investigates the BER performance of the SM-OFDM system, with the modified indoor environment simulated in [23]. Besides, first hardware implementation of a SSK system is analyzed in [26].…”