Multidimensional Media - Based Modulation

This paper compares the system performance of transmit diversity schemes for use in interference-limited cellular systems. We focus on evaluating the performance of Alamouti space time block codes (STBC) and cyclic delay diversity (CDD) codes, which are being actively considered for adoption within the 3 GPP-long-term-evolution (LTE) and 802.16e WiMAX standards. While the performance of transmit diversity schemes has been extensively evaluated in noise-limited scenarios, their performance in co-channel interference (CCI) limited cellular systems has received limited attention so far. As cellular systems adopt frequency reuse of one, co-channel interference from other cells becomes a major limitation to system performance. We present system simulation results comparing the performance of transmit diversity schemes using matched filter reception for a multi-carrier OFDM-based cellular system. In particular, the performance of STBC and CDD schemes is compared with respect to the evolving third generation 3 GPP-LTE standard. Our comparison highlights the spatial as well as the multi-user diversity aspects of these schemes and considers a variety of scenarios that will require their use. Our results show that CDD can significantly improve the system spectral efficiency and cell-edge performance over STBC, when used in combination with frequency-dependent scheduling. For open loop transmission without scheduling, the relative diversity gains of STBC and CDD at link layer depend on the interference scenario considered, while the system performance of these schemes is very similar.

This chapter looks at three important modulation paradigms. Trellis-coded modulation (TCM) is considered first. Developed in the late 1970s as a method to conserve bandwidth without sacrificing error performance it has become an extremely important modulation. The second technique is called code-division multiple access (CDMA). It falls within the broad class of multiple access methods and is an administrator's favorite. It makes the addition (or deletion) of new users essentially transparent, easing the administrator's work. However, the technique does have technical merits that warrant its study by communication engineers. It forms the basis for the so-called 3G (third generation) and beyond wireless communication systems. In contrast to TCM, CDMA is a very wideband modulation technique. The last modulation method studied uses space-time codes which provide diversity gain for the fading channel through the use of multiple transmit antennas. The important Alamouti's space-time block code (STBC) is discussed in some detail. It was first described in 1998, almost at the same time Tarokh et al . published their paper on space-time trellis codes. Trellis-coded modulation (TCM) By now one can appreciate that over an AWGN channel, the basic idea in digital communications is to find signal constellations with as large a distance between signals as possible without increasing the energy E b (joules) expended per bit inordinately and with as small a bandwidth as possible.

Recently, orthogonal time frequency space modulation with index modulation (OTFS-IM) has been proposed, which can achieve better bit error rate (BER) performance than conventional OTFS. In this letter, a new transmission scheme, OTFS with in-phase and quadrature index modulation (OTFS-I/Q-IM), is presented to increase the spectral efficiency of OTFS-IM, in which additional information bits are carried through the grid index of OTFS block in in-phase and quadrature dimensions. Furthermore, the analytical expressions of average bit error probability (ABEP) and the maximum peak to average power ratio (PAPR) are derived to evaluate the performance of the proposed scheme. Simulation results demonstrate the enhanced performance of the proposed scheme in high-mobility scenarios.

Orthogonal frequency division multiplexing with index modulation (OFDM-IM), which transmits information bits via <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$M$ </tex-math></inline-formula> -ary constellation symbols and indices of the active subcarriers, is a promising OFDM-based multicarrier transmission scheme. Recently, several new schemes have been proposed by utilizing the flexibility of the OFDM-IM to meet the diverse needs of 5G networks. Coordinate interleaved OFDM-IM (CI-OFDM-IM) that conveys the real and imaginary part of the data symbols over different subcarriers and OFDM with power distribution IM (OFDM-PIM) that transmits the data symbols over high and low power subcarriers, are two OFDM-IM based schemes with additional diversity gain and improved bit error rate (BER) performance. In this letter, we propose a novel transmission scheme named as coordinate interleaved OFDM with power distribution IM (CI-OFDM-PIM), which applies coordinate interleaving and power distribution in subcarriers to achieve a higher diversity gain. The average bit error probability (ABEP) for the CI-OFDM-PIM is derived and the superior error performance of the proposed scheme over benchmarks are shown via computer simulations.

In this paper, we propose a novel active reconfigurable intelligent surface (RIS)-assisted amplitude-domain reflection modulation (ADRM) transmission scheme, termed as ARIS-ADRM. This innovative approach leverages the additional degree of freedom (DoF) provided by the amplitude domain of the active RIS to perform index modulation (IM), thereby enhancing spectral efficiency (SE) without increasing the costs associated with additional radio frequency (RF) chains. Specifically, the ARIS-ADRM scheme transmits information bits through both the modulation symbol and the index of active RIS amplitude allocation patterns (AAPs). To evaluate the performance of the proposed ARIS-ADRM scheme, we provide an achievable rate analysis and derive a closed-form expression for the upper bound on the average bit error probability (ABEP). Furthermore, we formulate an optimization problem to construct the AAP codebook, aiming to minimize the ABEP. Simulation results demonstrate that the proposed scheme significantly improves error performance under the same SE conditions compared to its benchmarks. This improvement is due to its ability to flexibly adapt the transmission rate by fully exploiting the amplitude domain DoF provided by the active RIS.

In this paper, we propose to use Alamouti's orthogonal space-time block code to improve the performance and the robustness of the spread spectrum watermarking systems. After employing a space-time block code, we embed the coded watermark sequence into the host image in discrete wavelet transform domain. Simulation results show that the use of the space-time block codes considerably increases the robustness of the spead spectrum watermarking system under various attacks.

In this paper, a new multiple-input multiple-output (MIMO) transmission technique, which is called double spatial modulation (DSM), is proposed as a new high-rate generalized spatial modulation (SM) scheme. DSM scheme aims to improve the spectral efficiency of classical SM by increasing the number of active transmit antennas. In the DSM scheme, incoming data bits determine two modulated symbols as well as their corresponding activated transmit antenna indices. One of the modulated symbols is directly transmitted over its corresponding activated transmit antenna, while the other one is transmitted with a rotation angle, which is optimized for M-ary quadrature amplitude modulation (M-QAM) signal constellation, over the second activated transmit antenna. The error performance of the proposed DSM scheme is compared with the recently proposed emerging SM schemes such as quadrature SM (QSM) and enhanced SM (ESM). Our computer simulations show that the DSM scheme provides considerably better error performance than QSM and ESM schemes for different spectral efficiency values. In addition, the pairwise error probability (PEP) of DSM is derived and the average bit error probability (ABEP) over uncorrelated Rayleigh fading channels is obtained for different M-QAM constellations.

The Spatial Modulation (SM) transmission scheme boosts the spectral efficiency and achieves the multiplexing gain by activating a single transmit antenna in each time slot. Radio wave propagation characteristics determined by the environment is a decisive factor for the SM system. In this paper, we investigate the performance of the SM scheme over real-world 4×4 Multi-Input Multi-Output (MIMO) channels measured in typical indoor scenarios. Firstly, a MIMO channel sounder is established. Based on the sounder, 15150 complex 4×4 MIMO channel matrices are measured inside a typical teaching building under both Line of Sight (LOS) and None Line of Sight (NLOS) scenarios. Secondly, by comparing the SM system over the measured channel and commonly-used channel models, we prove that both the Independently and Identically Distribute (i.i.d.) Rayleigh and the Spatial Correlation (SC) channel model are oversimplified, and that only practical experiences can yield definitive answers to the achievable real-world system performance. Thirdly, the Average Bit Error Probability (ABEP) performance of the SM system is studied based on the measured data under a variety of system configurations. The study of different receive antenna array settings (4×4, 4×2 and 4×1 MIMO setups) approves the significance of combining scheme at the receiver. SM systems employing different signal constellations (Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 16 Quadrature Amplitude Modulation (16QAM)) are also investigated and some interesting results are revealed. Lastly, performance assessment of SM against State-Of-The-Art (SOTA) MIMO schemes (Space-Time Block Code (STBC) and Vertical Bell Labs Layered Space-Time (V-BLAST) code) is conducted. Results show that for a 4×4 MIMO, the low-complexity SM scheme outperforms both STBC and V-BLAST.

In this letter, we derive an exact closed-form expression for the bit error rate (BER) of an M-ary quadrature amplitude modulation (QAM) multiple-input multiple-output (MIMO) 2×N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> system that employs Alamouti's space time block code (STBC) transmission and maximal ratio combining (MRC) reception, when imperfect channel state information (ICSI) is considered in a Ricean fading channel. An approximate yet accurate expression for the BER is also provided when a strong line of sight (LOS) component is considered. It is observed that the loss of orthogonality of Alamouti's code due to ICSI leads to a non-negligible noise enhancement.

This paper presents a framework to design protograph low density parity check (LDPC) codes for wireless communications where Alamouti space time block code (STBC) scheme is exploited to combat with the fading effect and the number of decoding iterations is limited. The decoding threshold of the resulting protograph code is about 0.7 dB better than that of the state-of-the-art code in the literature. The simulation of the proposed code is reported, and simulation results confirm the analytical advantages of the design. No error floor is found down to frame error rate (FER) of 10−6.

Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation scheme widely used in 4G. It is effective for reducing the effects of multipath delay in wireless communication. For OFDM system, total delay spread (Td) is less than symbol period (T); it can be combined with antenna arrays at transmitter and receiver (MIMO) to increase diversity gain called as MIMO-OFDM system. MIMO-OFDM improves system capacity on time-variant and frequency-selective channels. The quality of service provided by a system greatly depends upon the correct selection of modulation scheme. In this paper, analysis and simulation of OFDM-MIMO system with different digital modulation schemes like BPSK, 8-PSK, QPSK, and QAM is performed using Alamouti space–time block codes (STBC). STBC uses spatial and time dimensions for error control unlike traditional methods that uses only time dimension. A comparison study shows that for a given data rate and channel conditions, OFDM-MIMO using STBC with BPSK modulation is better compared with other digital modulation techniques in terms of error performance. OFDM-MIMO using STBC with BPSK modulation is further analyzed and simulated for various antenna configurations. It is observed that as numbers of antennas at transmitter and receiver side are increased, the system diversity increases and gives better performance in terms of BER.

The Alamouti Space Time Block Code (STBC) based Orthogonal Frequency Division Multiplexing (OFDM) is very attractive in frequency selective channel as the channels remain constant over Alamouti code period (two consecutive OFDM symbol block). But when the channel is fast fading, this assumption does not holds good and causes co-channel interference (CCI). Hence, the simple Alamouti detection method is not sufficient to recover the original transmitted signal from the mixed transmitted signals at the receiver side. To cancel the effects of CCI, several detection techniques are addressed namely SIC, DMLD, DZFD, DF and ML. The ML method has the optimum performance but the computational complexity is very high. Therefore, we propose a suboptimal MDF detection which provides comparable performance to that of ML with very less computational complexity. Finally, the performances of the above detection methods are compared in terms of symbol error rate (SER) and computational complexity for STBC OFDM system over doubly selective channel.

The idea of media-based modulation (MBM), introduced in [1] [2], is to embed information in the variations of the transmission media (channel states). This is in contrast to legacy wireless systems which embeds data in a radio frequency (RF) source prior to the transmit antenna. MBM offers several advantages over legacy systems, including “additivity of information over multiple receive antennas” and “inherent diversity over a static fading channel”. MBM is particularly suitable for transmitting high data rates using a single transmit unit and multiple receive antennas (single input multiple output MBM, or SIMO-MBM). Furthermore, layered multiple input multiple output MBM (LMIMO-MBM) [3] addresses hardware and decoding complexity along with training overhead when transmitting high data rates using a single MBM transmit unit. The current article compares the performance of MBM and LMIMO-MBM vs. legacy multiple input multiple output (MIMO) and emerging modulation techniques, spatial modu-lation (SM), and its variants, such as generalized SM (GSM) and quadrature SM (QSM). These comparisons demonstrate considerable performance gains for MBM and LMIMO-MBM vs. these notable schemes.

In this paper, we propose a novel Multiple Input Multiple Output (MIMO) scheme based on Spatial Modulation (SM) and termed as Pre-coding aided Differential Spatial Modulation (PDSM). By mapping information to the receiver side space-time transmit blocks and conducting differential modulation, the PDSM scheme achieves further reduced receiver side complexity in comparison with Pre-coding aided Spatial Modulation (PSM). A general upper bound on the Average Bit Error Probability (ABEP) achieved by the PDSM architecture with an arbitrary number of transmit antennas and two receive antennas is derived, and an exact closed-form ABEP expression is provided for BPSK signaling in Rayleigh fading environment. The PSM architecture with the same system configuration is chosen as a benchmark for performance comparisons. Simulation results validate the analysis and reveal a less-than-3dB Signalto- Noise power Ratio (SNR) penalty of the considered system in comparison with the benchmark.

This paper propose a new multiple-input multipleoutput (MIMO) signal processing scheme that combines optimum transmit and receive beamforming with the Alamouti space-time block code (STBC) transmission and modifies the decoding process. The scheme uses double antenna array groups to achieve stable performance regardless of direction of arrived (DOA) and angular spread (AS). In a multiuser MIMO communications scenario, the beamforming suppresses co-channel interference (CCI) by maximizing the uplink signal-to-noise-plus-interference-ratio (SINR) and suppress CCI independently while preserving orthogonality of the MIMO channel. It is shown that the beamforming process provides array gain by increasing the bit-error-rate (BER) performance and maximizes the available uplink channel capacity for each user in the presence of CCI.