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Summary: In this paper, a non‐orthogonal multiple access (NOMA)‐based precoded quadrature spatial modulation (PQSM) technique (NOMA‐PQSM) has been proposed for the downlink scenario. In NOMA‐PQSM, two intended receiving antennas are activated at any time instant. One antenna is activated for the in‐phase component of the transmitted signal, and another one is activated for the quadrature phase component, on the basis of data bits. NOMA‐PQSM provides benefits like improved spatial diversity and spectral efficiency in comparison with spatial modulation. This work uses zero forcing (ZF) precoding over downlink flat fading Rayleigh multiple input multiple output (MIMO) channels, to limit the channel's deteriorating effect on transmitted signal, assuming perfect channel state information (CSI) at the transmitter. A low complexity receiver based on the successive interference cancellation is used. An expression for the upper bound of average bit error probability is derived. Moreover, the expressions for the sum mutual information of users and its lower bound are also derived. The proposed scheme is compared with the preprocessing aided spatial modulation (PSM)‐based counterpart. Monte Carlo simulations reveal that the NOMA‐PQSM scheme outperforms its orthogonal counterpart and the PSM scheme. [ABSTRACT FROM AUTHOR]

ABSTRACT The spectrum sensing is a major significant task in cognitive radio networks (CRNs) to avoid the unacceptable interference to primary users (PUs). Here, the threshold value determines the effectiveness of spectrum sensing and regarded as a sensing system. The fixed threshold used by the current energy detection‐based spectrum sensing (SS) techniques does not provide sufficient safety for the main users. The threshold is determined by lowering the complete probability of decision error in addition to these guidelines. Therefore, an energy detection using nonparametric amplitude quantization optimized with arithmetic optimization algorithm for enhanced spectrum sensing in CRNs (ED‐NAQ‐AOA‐SS CRN) is proposed in this paper to acquire the ideal threshold for decreasing the total error probability. The proposed method achieves greater probability of detection of 99.67%, 98.38%, 92.34%, and 97.45%, lower settling time of 98.33%, 89.34%, 83.12%, and 88.96%, and lower error rate of 93.15%, 91.25%, 79.90%, and 92.88% compared with existing techniques, like intelligent spectrum sharing and sensing in CRN with adaptive rider optimization algorithm (AROA), a novel technique for spectrum sensing in CRN utilizing fractional gray wolf optimization with the cuckoo search optimization (GWOCS), and adaptive neuro‐fuzzy inference scheme depending on cooperative spectrum sensing optimization in CRNs (ANFIS). [ABSTRACT FROM AUTHOR]

Summary Perfect detection of unused/underutilized frequency band of the primary user (PU) in the cognitive radio communication systems is an essential component for its efficient utilization by the secondary/cognitive user (CU) without any interference. In the cooperative spectrum sensing scenario, the presence or absence of PU is determined by analyzing the decisions of each CU engaged in the collaboration. In this paper, we have emphasized on the significance of spectrum sensing duration in the optimal threshold selection approach in the cooperative spectrum sensing scenarios for a range of the received PU signal signal‐to‐noise ratio (SNR) from low to high values. The sensing duration parameter is taken as ts = 2.5 ms in the higher SNR environment, whereas in the lower SNR environment when the optimal threshold condition fails, ts is kept dynamic to satisfy minimum target values of sensing performance parameters. We have computed the spectrum sensing performance parameters and throughput using the same approach and compared the results with those obtained from the constant false‐alarm rate (CFAR), constant detection rate (CDR), and minimized error probability (MEP) threshold selection approaches. The spectrum sensing performance computed by the proposed approach is significantly improved as compared with the other reported approaches. At SNR = −24 dB, global probability of false alarm Qf = 0.002 and global probability of detection Qd = 0.999 are achieved. However, the throughput is relatively less for low SNR values. [ABSTRACT FROM AUTHOR]

Summary: In practice, hardware impairments (HIs) often exist in wireless devices, especially in low‐cost device systems. However, previous reports usually ignored HIs due to the computational complexity in mathematical derivations, particularly in millimeter‐wave (mmWave) communications. This article proposes the usage of transmit antenna selection (TAS) and multiple reconfigurable intelligent surfaces (RISs) to address HIs in mmWave communications. In particular, TAS is utilized at the source to increase the received signal power at the destination and reduce the effects of HIs. Multiple channel gains from RISs are combined with the classical source‐destination channel gain at the destination. The symbol error probability (SEP) expression of the mmWave communications with TAS and RISs under the effects of HIs (shortened as the TAS‐RISs‐HIs communications) is formulated over Nakagami‐ m channels and verified through Monte Carlo simulations. The effects of HIs on the SEP of TAS‐RISs‐HIs communications are demonstrated through numerical illustrations. Specifically, the SEP of the TAS‐RISs‐HIs communications is significantly higher than the SEP of the ideal hardware communications with TAS and RISs, especially in the high transmit power regime. As a result, ignoring HIs when evaluating the SEP of the mmWave communications can result in some inappropriate conclusions. Moreover, the joint and separate advantages of TAS and RISs are thoroughly analyzed when comparing the SEPs in the cases with and without TAS, with and without RISs. [ABSTRACT FROM AUTHOR]

Summary: In this article, the performance of a wireless communication system with an intelligent reflecting surface (IRS) panel installed between the transmitter and receiver is studied. The channel is considered to be the Hoyt faded and additive white Gaussian noise. Closed‐form expressions for average bit error probability (ABEP) for both coherent Gray‐coded rectangular quadrature amplitude modulation and non‐coherent modulation schemes are presented. We apply the moment‐generating function‐based method for the derivation. In addition, asymptotic ABEP expressions are also obtained. Using asymptotic ABEP expressions, we obtained diversity order which is a function of the number of IRS elements. The effect of the number of IRS elements and fading parameters on the ABEP is studied. The ABEP performance improves with an increase in the number of reflecting elements but degrades with an increase in the fading severity. The accuracy of each analytical ABEP expression is verified by the simulation of the system considered herewith. [ABSTRACT FROM AUTHOR]

Summary: Full duplex (FD) technique has evolved as a viable solution to address the spectrum scarce issue. It has gained research interest for its potential to double the wireless link capacity and enhance spectral efficiency (SE). In this paper, the end‐to‐end performance of an amplify‐and‐forward full duplex relay(FDR) in asymmetric Rayleigh–Rician fading channels is explored, unlike the other works that assume symmetric fading conditions in both the links. The asymmetric or mixed fading channels properly model the realistic communication scenarios like satellite/terrestrial wireless communication systems. In this work, we consider that the source‐relay link experiences Rayleigh fading and the relay‐destination link experiences Rician fading. The novel exact and lower bound closed form analytical expressions for outage probability (OP) and bit error rate (BER) for the considered FD system are derived. Moreover, the effect of severity of fading and the amount of residual self‐interference (RSI) on the performance of FDR are also studied. In addition, MC simulations are carried out to validate the results. It is observed that the performance metrics, OP and BER, are highly dependent on the severity of fading and the amount of RSI. Furthermore, it is found that typically at the SNR of 10 dB, an improvement of approximately 27.6% in OP is obtained. Also, our work offers appreciable SNR gain, for example, for a BER of 10−2, an SNR improvement of around 11 dB is achieved. These findings have been compared with the mixed Rayleigh–Rician fading channel conditions considering only half duplex(HD) mode. These parameter metrics are helpful in analyzing the performance of FD in various communication scenarios such as LoS/NLoS conditions and hence pave the way for more realistic FDR. [ABSTRACT FROM AUTHOR]

Summary: This paper analyzes the performance of maximal ratio transmission (MRT)‐based cooperative communication system over Nakagami‐ m fading channels in the existence of co‐channel interference which is becoming a critical factor since the limited spectrum bands are shared by growing number of devices. In particular, a dual‐hop decode‐and‐forward relaying is investigated when multiple interferers affect the relay and the destination nodes. Firstly, the cumulative distribution function (CDF) and the probability density function (PDF) of the signal‐to‐interference‐plus‐noise ratio (SINR) are derived. Then, the exact expressions for the outage probability (OP), average bit error probability (ABEP), and ergodic capacity are obtained. Furthermore, asymptotic expressions for OP and ABEP are provided to find the diversity and coding gains. Finally, simulation results are presented to validate our theoretical findings. [ABSTRACT FROM AUTHOR]

Summary: The user far from the base station (BS) can decode the signal via direct transmission or a relay network, but it cannot achieve higher throughput because of its high error probability. The MIMO‐NOMA‐Relay networks are replaced by MIMO‐NOMA‐RIS to achieve higher throughput in the proposal. The MIMO‐NOMA‐RIS sends a superimposed signal to the receiver using a multiple RIS beam scanning algorithm. They can improve the strength of the signal as well as improve the throughput and reduce the probability of error. As more reflecting surface area increases, the strength of the beam‐forming signal also increases, which means that the user could receive more signal strength than the direct transmission, amplify and forward (A&F) relay network. In multi‐user case, use the max–min power control algorithm (MMPCA) to allocate optimum power to a weaker channel strength user and achieve an optimum result. Method 1 used a single user with RIS to find the system equations. In both single‐user and multi‐user scenarios, we use MIMO‐NOMA‐RIS. Our proposed method's complexity is low because of its simplicity. In our proposed method, the MMPCA is used for optimum power allocation, and the resulting non‐convex function is converted into a convex one by using successive convex approximations. The result section shows that the RIS achieved the highest throughput and the lowest probability of error. [ABSTRACT FROM AUTHOR]

Summary: The space‐time line code (STLC), which has been recently proposed in the literature, assumes fully known channel state information at the transmitter and not the receiver. However, the effective channel gain is still required at the receiver to coherently detect M‐ary quadrature amplitude modulation (MQAM) symbols. In this paper, we propose pilot‐aided STLC systems, which do not require the effective channel gain at the receiver to detect the MQAM symbols. In order to further improve the error performance of the proposed schemes, we present the pilot‐aided STLC systems with transmit antenna selection (TAS). Using a more direct and simpler approach, we derive the average symbol error probability (ASEP) of the coherent 1×2 STLC systems with TAS, which represents the lower bound of the pilot‐aided 1×2 STLC systems with TAS. For comparison, in a similar manner, we also derive the ASEP of the coherent 2×2 STLC systems without TAS, which represents the lower bound of the pilot‐aided 2×2 STLC systems. For pilot‐aided 1×2 STLC systems with TAS, the gap between the simulated symbol error rate (SER) and the derived theoretical ASEP lower bound is very small. For a given number of transmit antennas, the simulated SER and theoretical ASEP also show that the error performance of the pilot‐aided 2×2 STLC systems with or without TAS is superior to the pilot‐aided 1×2 STLC systems with TAS by at least 1.8 dB. [ABSTRACT FROM AUTHOR]

Summary: In a cooperative spectrum sensing (CSS) network, the primary signal can be used as a radio frequency (RF) source in order to power the energy‐constrained sensor nodes of the secondary network. This work presents a novel hybrid model combining an optimal relay selection scheme to incorporate RF energy harvesting in a centralized CSS network. The secondary users, which are equipped with RF energy harvesting capabilities, act as relays in order to forward the sensing information to a fusion center. Here, we have derived an enhanced multi‐relay selection strategy to maximize the end‐to‐end signal‐to‐noise ratio of the links. Furthermore, a new voting rule is proposed based on the generalized K‐out‐of‐M rule, such that it minimizes our objective error function. The performance analysis of our proposed model is presented with respect to the flexible relay positions. We have used complementary receiver operating characteristic curves for analyzing the detection performance of the CSS model with our derived voting rule. Simulation results using MATLAB show that the proposed model gives a better detection probability and a smaller error rate than some related existing works. [ABSTRACT FROM AUTHOR]

Summary: Cooperative communication is a significant technology for fifth generation (5G) and beyond wireless communication to improve the quality of service (QoS) in massive networks. In addition, it serves as a promising candidate along with non‐orthogonal multiple access (NOMA) scheme to increase the spectral efficiency. Conventionally, cooperative‐NOMA (C‐NOMA) systems are analysed by assuming perfect successive interference cancellation (SIC) and imperfect SIC (I‐SIC) over Rayleigh, Rican, α−μ, Hoyt fading channels, and so on. In this paper, near–far relay (NFR) C‐NOMA system is analysed aiding perfect SIC, perfect channel state information (CSI), imperfect (I‐CSI) and (I‐SIC) over Rayleigh fading channel. Initially, we derive analytical expressions of outage probability (OP) by considering I‐SIC and I‐CSI for NFR‐C‐NOMA system. The accuracy of analytical results is verified through Monte Carlo (MC) simulations. Interpretation of the results conveys that I‐CSI and I‐SIC have a substantial impact on OP in NFR‐C‐NOMA scheme and existing schemes. Later, we examined impact on OP in NFR‐C‐NOMA by varying relay position, target rate of users and jointly considering the I‐SIC, I‐CSI. Further, it is also observed that the NFR‐C‐NOMA scheme shows better outage performance than state‐of‐the‐art schemes. [ABSTRACT FROM AUTHOR]

Summary: Paper has considered multiple reconfigurable intelligent surfaces (RISs) assisted downlink non‐orthogonal multiple accesses (NOMA) system, referred to as MR‐NOMA. Multiple RISs create a line‐of‐sight (LOS) channel between BS and users to improve network coverage, especially in high frequencies and severe path attenuation scenarios. In MR‐NOMA, all RISs are in series and activated simultaneously; therefore, multiplicative beamforming gain from the inter‐RIS channels is achieved. Bit error probability (BEP) under the Rician fading channel is derived and compared with simulation results. It is observed that BEP performance depends on the number of passive reflecting elements, Rician factor, and positions of RISs panels in the MR‐NOMA. [ABSTRACT FROM AUTHOR]

Summary: This study presents the average symbol error probability (ASEP) performance of a single‐input single‐output communication with imperfect phase error (IPE) and without IPE over the Beaulieu‐Xie fading channels. The Beaulieu‐Xie fading model is proposed recently and it is a popular characterization for the line‐of‐sight and non‐line‐of‐sight environments. The proposed theoretical analysis, which is based on the probability density function, is enough general and applicable in some real‐life scenarios. For both cases, closed‐form exact, approximate, and asymptotic expressions are derived for the ASEP of different modulation types. Finally, exact simulations have been introduced to confirm the accuracy of the theoretical findings obtained and present insights into the considered scheme performance. [ABSTRACT FROM AUTHOR]

Summary: The recently proposed quadrature spatial modulation aided single‐input multiple‐output media‐based modulation (QSM aided SIMO‐MBM) improves the spectral efficiency and achieves a high data rate and overall system error performance when compared with conventional SIMO‐MBM and SIMO schemes. Cooperative network (CN) involves collaboration among nodes to improve wireless network reliability, link quality, and spectral efficiency. This paper investigates the performance of QSM aided SIMO‐MBM in CN by employing the decode and forward relaying technique, which utilizes two source nodes that simultaneously transmit a unique message block on the same time slot to the relay node; the relay node decodes the received message block from both transmitting nodes, before re‐encoding and re‐transmitting the decoded message block in the next time slot to the destinations in order to enhance the error performance of the QSM aided SIMO‐MBM further. Each node can decode the data of the other node using network coding (NC) techniques. Algebraic algorithms are applied to the detected message to accumulate the various transmissions. The theoretical average error probability of the proposed scheme was formulated using a lower bound technique, and the Monte Carlo simulation (MCS) results obtained validated the result. The MCS results achieved exhibit a significant improvement of 8 dB at 6 b/s/Hz for a BER of 10−5 and 12 dB at 8 b/s/Hz for a BER of 10−5 over the conventional QSM aided SIMO‐MBM scheme. Consequently, the obtained results show that the system configuration with mrf=2 outperforms the system configuration with mrf=4 for the proposed scheme. [ABSTRACT FROM AUTHOR]

Summary: It has been confirmed by many scientists and industrial experts that intelligent reflecting surface (IRS) should be one of the key enabling technologies for sixth‐generation (6G) wireless networks. This paper analyzes the performance of an IRS‐aided full‐duplex (FD) amplify‐and‐forward wireless relay (AFR) network, where the IRS is exploited to enhance the quality of the channel from the source to the relay. We successfully derive the analytical expressions of outage probability (OP), achievable data rate (ADR), and symbol error probability (SEP) of the considered IRS‐FD‐AFR network over Rayleigh fading channel. The corresponding expressions of the IRS‐aided half‐duplex (HD) AFR (IRS‐HD‐AFR) system are also derived as a benchmark to compare. The results demonstrate that the performance of both IRS‐FD‐AFR and IRS‐HD‐AFR systems are greatly improved by increasing the number of reflecting elements (L) in the IRS. All derived expressions are validated by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Summary: The receiver of a conventional differential modulation scheme performs detection without knowledge of the channel state information (CSI). This results in a 3 dB performance loss compared to coherent modulation. In order to enhance this error performance, generalised differential modulation is utilised. This paper extends the generalised differential modulation scheme to multiple‐input symbol Golden code (MIS‐GC) and proposes a multiple‐input symbol generalised differential Golden code (MIS‐GD‐GC) scheme. This scheme improves the error performance when compared to conventional differential MIS‐GC and achieves a diversity order of 2lNr compared to the conventional Golden code, where l ≥ 1 is an integer, Nr is the number of receive antennas and 2l represents the number of multiple‐input symbols in the MIS‐GC system. We also derive the average bit error probability for the MIS‐GD‐GC scheme. The simulations of bit error rate (BER) compare very well to the derived theoretical bounds and show that the BER of MIS‐GD‐GC draws closer to that of coherent MIS‐GC as the frame length increases. For instance, at a frame length of B=400, the error performance gap between MIS‐GD‐GC and its coherent counterpart is only 0.4 dB. [ABSTRACT FROM AUTHOR]

Summary: Non‐orthogonal multiple access (NOMA) is a technique to improve spectral efficiency. Based on the constellation relationship (CR) between the superposition‐coded signal and individual user's signals, in the literature, a simple detection scheme threshold‐based signal detection has been proposed for the two‐user downlink NOMA (DL‐NOMA) system with specific power allocations, not arbitrary power allocation. Furthermore, the average symbol error probability (ASEP) with squared M‐ary quadrature amplitude modulation for two‐user DL‐NOMA systems has also been derived based on this CR. Based on the threshold‐based signal detection for the two‐user DL‐NOMA systems with specific power allocation, in this paper, a generalized threshold‐based signal detection is proposed for all users in the multiuser DL‐NOMA systems with arbitrary power allocation, and then a fast generalized threshold‐based signal detection is further proposed. The generalized ASEP for each individual user in the multiuser DL‐NOMA system is further derived in Rayleigh fading channels. Both theoretical ASEP and simulated symbol error rate results validate the fast generalized threshold‐based signal detection scheme and the generalized ASEP for multiuser DL‐NOMA systems with arbitrary power allocations. [ABSTRACT FROM AUTHOR]

Summary: The advancements towards the 5G technology are significantly reliant on the effective utilization of the radio spectrum. The scarcity of the spectrum is a barrier to the employment of emergent wireless multimedia. The cognitive radio (CR) technology has materialized as a reassuring remedy to the present problem of spectral scarcity. This study explores the statistical characterization of energy detector‐based cognitive radio device alongside diversity reception. The analysis is carried out with the postulation that the transmitting signal encounters fading, characterized by α‐μ fading channel. Initially, we present a PDF expression of the α‐μ fading model when subjected to maximal ratio combining (MRC) diversity reception. Utilizing this expression, the closed‐form expression of the average probability of detection (Pd) and the average area under the receiver operating characteristics curve (AUC) are derived in the terms of Fox's H function. The detection threshold has been optimized to improve the detection performance by curtailing the probability of error. Additionally, asymptotic results for Pd with various diversity combining cases are also obtained under high signal‐to‐noise‐ratio (SNR) regime. Furthermore, the result of Pd is applied to explore the execution of cooperative spectrum sensing (CSS) with diversity reception. The accuracy and validation of the presented results are assured by comparison with the Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

Summary: Recently, intelligent reflecting surface (IRS)‐based communication systems are analyzed for 6G and beyond wireless networks. In this paper, we propose an IRS‐assisted downlink nonorthogonal multiple access (NOMA) system by considering separate IRS for near users (NUs) and far users (FUs). The optimal power allocation strategy among NUs and FUs is formulated for the proposed downlink IRS‐NOMA system. The symbol error probability and the sum‐rate performance of the IRS‐NOMA system are analyzed. Further, the impact of the modulation order, the number of reflecting surfaces, the number of phase shifts of reflected signals on symbol error, and power allocation between NU and FU is studied. [ABSTRACT FROM AUTHOR]

Summary: Wireless body area networks (WBANs) dynamically track a person's health data wirelessly. The implant‐to‐implant communication (CM1) inside the human body requires low power, highly reliable channels amidst the high losses and attenuation due to the various portions of the body. This attenuation and noise results in complete variation of the monitored health data, resulting in faulty medical diagnosis and alarms. Low density parity check (LDPC) algorithms are popular for error correction in this scenario. However, they still need to be improved for a more reasonable analysis of the health status. We suggest processing of the sensed data to increase the sparsity, thereby improving the bit error probability performance of the LDPC coding technique. Further, we propose the use of Kalman filter to estimate the actually transmitted bit from the LDPC decoded message output. The simulation results show that the proposed technique improve the error correction capability of the LDPC code. The increased energy, time and computations required for the same is found to be within a satisfactory level for the proper functioning of the WBANs. [ABSTRACT FROM AUTHOR]

Summary: In this work, we have comprehensively investigated the impact of non‐linearity (α − μ) and shadowing (inverse gamma) collectively over the wireless channel. To this effect, an approximate closed‐form probability density function (PDF) expression is derived over α − μ/inverse gamma fading channel by employing Gauss–Laguerre quadrature polynomial. The accuracy of the proposed approximate solution is validated through the Kullback–Leibler divergence test. Subsequently, the proposed solution is utilized in the development of various fundamental statistics like commutative distribution function (CDF), moment generating function (MGF) and nth moment. This contribution also includes the derivation of coding gain and diversity gain to study average symbol error probability (SEP) with MRC and EGC diversity. It is observed that diversity gain is independent of shadowing and as the channel condition improves, the coding gain decreases. Finally, the closed‐form solutions of spectral efficiency under different adaptive transmission policies are also developed specifically, optimal power and rate adaptation (OPRA) and effective capacity along with simpler low‐ and high‐power expressions. Monte‐Carlo simulations are utilized to validate the proposed analytical and numerical results. [ABSTRACT FROM AUTHOR]

Summary: Single‐input multiple‐output media‐based modulation (SIMO‐MBM) improves the limitation of single‐input multiple‐output (SIMO) systems by minimizing the required number of antennas to achieve a high data rate and enhanced error performance. In this paper, we employ the quadrature dimension of the spatial constellation by decomposing the amplitude/phase modulation (APM) symbol into real and imaginary components similar to quadrature spatial modulation (QSM) to improve the overall error performance of the conventional SIMO‐MBM and to achieve a higher data rate. The average bit error probability of the proposed scheme is formulated using a lower bound approach and validated by the Monte Carlo (MC) simulation results obtained. Furthermore, the effect of the suboptimal mirror activation pattern selection using channel amplitude coupled with antenna correlatio n is examined for the proposed system. The MC simulation results achieved demonstrate a substantial improvement of 3.5 dB at 10 b/s/Hz with mrf = 2 and 7 dB at 12 b/s/Hz with mrf = 4 over the conventional SIMO‐MBM scheme. [ABSTRACT FROM AUTHOR]

Summary: This paper addresses the performance of wireless fading channels, namely, Rayleigh, Rician, and Nakagami‐m fading channels, taking both noiseless and additive noisy cases into account. The performance metrics investigated are channel capacity, channel model variance estimation, required average description length based on Shannon entropy, and relative entropy and symbol error probability assessment. Taylor expansion is considered as an approximation for the aforementioned metrics together with the compressed sensing (CS) compressibility rule. Technical comments are provided for supporting simulation results. Mathematical interpretations are provided to support the simulation results along with feasible applications in 5G wireless systems. Conclusions and future research directions finalize the paper. [ABSTRACT FROM AUTHOR]

Summary: The performance of radio‐frequency (RF) networks where channels are modeled by an extended‐generalized‐K (EGK) distribution and consider significant phase errors during coherent detection at the receiver due to carrier‐phase‐synchronization‐mismatch is investigated in this work. The performance is evaluated for a single‐hop link and two‐hop amplify‐and‐forward (AF) and decode‐and‐forward (DF) relay‐assisted RF links. The EGK is a generalized distribution, which can model various fading conditions in millimeter (mm)‐wave wireless channels where transmission frequency is 60 GHz and above and takes into account non‐homogeneous propagation, interference effects in a multiuser transmission environment, multipath fading and shadowing effects. The average symbol error probability (ASEP) performance is evaluated for a single‐hop link when carrier is modulated using multilevel PSK modulation scheme. Based on the analytical results obtained for a single‐hop link, the mathematical analysis for the error performance in widely employed AF and DF relay‐assisted RF two‐hop networks is developed and ASEP is derived. To quantify the degradation in system performance introduced by phase errors, the reference‐carrier phase estimation loss for a single‐hop RF link is also evaluated. The obtained analytical results are also verified by numerical plots and depict the effects of various channel conditions existing over the RF link and phase synchronization errors. [ABSTRACT FROM AUTHOR]

Summary: Decoding of frequency‐hopping spread spectrum (FHSS) methods to intercept the symbol content in signals and brilliant measurement is presented in this paper. The switching of the frequency channels rapidly using a pseudorandom code makes interception of FHSS signals very difficult. Therefore, a proposed adaptive compressive measurement for decoding the frequency‐hopping receivers that have no prior knowledge of the hopping sequence is the main focus of this work. The proposed methods rely on the instantaneous sparsity of the spectra of FHSS signals, and the transmitted symbols can be recovered from the proposed compressive measurements. Furthermore, the contribution of this work is the design of a proposed adaptive method that is used to design measurement kernels for compressive measurement and decoding based on knowledge enhancement, which includes both prior information enhanced and adaptive methods based on the properties of the intersignals. Simulation results on Gaussian frequency‐shift keying (GFSK) FHSS signals illustrate that the proposed compressive method enhances the detection performance of the received frequencies with acceptable decoding accuracy compared with other techniques such as enhanced orthogonal matching pursuit (EOMP) and an adaptive sampling kernels method with a random compressive ratio. Also, an enhancement of the proposed algorithm is achieved due to enhancement in both the normalized mean square error (NMSE) and the probability of correction error (Pce). The comparison between these algorithms is performed using simulation based on MATLAB and receiver operating characteristic (ROC) curves. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a generalized solution to the symbol error probability (SEP) integral containing the product of two Gaussian Q‐functions QaγQbγ. Numerical integration technique is first used to approximate the polar form of QaγQbγ as a sum of exponentials. This approximation is then used to derive a closed‐form solution to the related SEP integral. Due to the exponential nature of the approximation, solution to the integral is expressed in terms of moment generating function (MGF) of a fading distribution. Therefore, the solution to integral exists for all fading distributions which have well‐defined MGF. The mathematical complexity of the proposed solution is directly proportional to the complexity of MGF expression. For most of the fading models, the corresponding MGF involves power or exponential functions, which guarantees algebraic simplicity of the proposed solution. Further, this generalized solution is used to evaluate the SEP of various modulation schemes over different fading channels. Various computer simulations run in MATLAB for wide range of scenarios confirm the accuracy of the proposed approximation and solution. [ABSTRACT FROM AUTHOR]

Summary: In the current digital era, there is a need of secure and efficient nanocommunication systems with ultralow power consumption. One technology that can be used for designing these systems is the quantum‐dot cellular automata (QCA). In the nanoregime, QCA is able to operate with higher speed and lower power dissipation compared with complementary metal oxide semiconductor technology. This work explores the applicability and feasibility of polar encoders, which felicitates reliable data communication with reduced probability of error, in nanocommunication systems. In this paper, (8,4) polar encoder is proposed in QCA technology. The proposed design is a single‐layer structure designed using only 600 cells consuming cell area of 0.1944 μm2 and total area of 0.7225 μm2 with a latency of 3.75 clock cycles, which results in a cost of 10.16. Based on the performance comparison, it is observed that the proposed design is cost‐efficient and achieves improvement up to 49.49% in terms of number of cells and area consumption, 40% improvement in latency, and 86.42% improvement in terms of cost compared with the only design in the literature. In addition to this, the energy dissipation analysis of the proposed designs is also presented. Hence, the proposed designs can be efficiently utilized in nanocommunication systems requiring minimal area and ultralow power consumption. [ABSTRACT FROM AUTHOR]

Summary: A new high‐performance low‐complexity cooperative maximal ratio combining (C‐MRC)‐based cooperative relaying scheme, which is called antenna selection‐aided cooperative spatial modulation scheme with C‐MRC (AS‐CSM), is proposed for decode and forward (DF)‐based cooperative relaying networks operating over independent but non‐identically distributed (i.n.d.) Rayleigh fading channels. The AS‐CSM scheme is formed with the combination of cooperative SM with the high‐performance low‐complexity coherent demodulator C‐MRC and antenna selection techniques. In the AS‐CSM scheme, the information is transmitted from the source terminal (ST) to the relay terminal (RT) and the destination terminal (DT) in the form of not only modulated symbols but also antenna indices, which carry additional information bits in the spatial domain. Therefore, a high spectral efficiency is obtained by the proposed scheme for cooperative relaying networks. In this scheme, first, the index of the activated antenna of ST is estimated, and the best antenna selection at RT is investigated considering the received instantaneous equivalent to signal‐to‐noise values acquired at DT. The transmitted symbols are estimated with low‐complexity coherent demodulator C‐MRC at DT by using the noisy signals from ST and RT. An exact closed‐form expression for the bit error probability (BEP) of the AS‐CSM scheme is derived, and the theoretical results are validated with Monte‐Carlo simulation results. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the exact analysis of a multihop multibranch (MHMB) relaying network is investigated wherein each relay can operate in amplify‐and‐forward (AF) or decode‐and‐forward (DF) modes depending upon the decoding result of its received signal. If a relay decodes the received signal correctly, it works in DF mode; otherwise, the relay operates in AF mode. Therefore, we name such relaying network as hybrid amplify‐and‐forward and decode‐and‐forward (hybrid AF/DF) relaying network. We first investigate the signal transmission from source to destination node via n number of relays in a hybrid AF/DF MHMB mode. Then, we obtained the statistical features and analyze the end‐to‐end signal‐to‐noise ratio (SNR). Finally, a comprehensive performance analysis is conducted by using maximal ratio combining (MRC) scheme at the destination node. For comparison, we also obtained the results using selection combining (SC) scheme at the destination node. To the best of our knowledge, very few works in the literature have considered a general system model of MHMB relaying network wherein each relay can operate in AF or DF modes, that is, a hybrid AF/DF relaying network. Accordingly, the analysis of our system model is not only novel and exact, but also is comprehensive and can be employed in the future works. [ABSTRACT FROM AUTHOR]

Summary: In this work, we investigate the performance of a dual‐hop cooperative network over α−μ fading channels with the presence of co‐channel interference (CCI) at both the relay and destination nodes. Amplify‐and‐forward (AF) relaying is considered in the relay node. The upper bound of the signal‐to‐interference‐plus‐noise ratio (SINR) of the dual‐hop relay link is used to determine the system performance. The probability density function (PDF) and the cumulative distribution function (CDF) of the upper bound of the SINR are analyzed. The system performance is determined in terms of the outage and error probabilities. Numerical results are used to present the performance analysis of the system. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we first investigate the effect of mobility via the random waypoint (RWP) mobility model on the performance of nonaccess point (non‐AP) or AP large intelligent surfaces (LISs). The theoretical average bit error probability (ABEP) for each of these LISs under mobility is formulated. The presented formulation is complicated to solve; hence, the trapezoidal approximation is employed. Simulation results serve to validate the ABEP. Second, we investigate a two‐way relaying (TWR) network assisted by non‐AP or AP LISs. A network with two source/destination nodes with a single relay node employing decode‐and‐forward placed between these nodes is considered. The transmission interval is broken into two transmission phases. In the first phase, the two source nodes transmit information blocks to the relay node assisted by LISs. On receiving these information blocks, the relay node decodes the two information blocks and encodes these into a single information block via the use of network coding. In the second phase, the relay node forwards the network‐coded information block to the destination nodes assisted by LISs, where the intended information block is decoded via network coding. The theoretical ABEP is formulated for the proposed non‐AP and AP LIS‐assisted TWR schemes and is validated by simulation results. RWP mobility is also demonstrated for the proposed TWR schemes. [ABSTRACT FROM AUTHOR]

Summary: Uncoded space‐time labelling diversity (USTLD) is a recent scheme that improved the error performance compared to conventional multiple‐input, multiple‐output systems. Thus far, USTLD has suffered from limited achievable data rates, as the original model uses only two transmit antennas. This motivates for the work in this paper, where the USTLD model is extended to allow for any desired number of transmit antennas. An analytical bound for the average bit error probability of this high‐rate USTLD (HR‐USTLD) system is derived. This expression is verified using the results of Monte Carlo simulations, which show a tight fit in the high signal‐to‐noise ratio region. The increased data rates associated with larger transmit antenna arrays in HR‐USTLD systems come at the cost of increased detection complexity. Therefore, this paper studies the application of low‐complexity detection algorithms based on the popular QR decomposition technique and proposes a new algorithm specifically designed for HR‐USTLD systems. Analysis of this algorithm in terms of accuracy and computational complexity is also provided and benchmarked against maximum‐likelihood detection (MLD). It is shown that the proposed algorithm achieves near‐MLD accuracy, while reducing complexity by 79.75% and 92.53% for the respective 4 × 4 16QAM and 4 × 5 16PSK HR‐USTLD systems investigated. [ABSTRACT FROM AUTHOR]

Summary: In this paper, the closed‐form expressions for outage probability, channel capacity, and average symbol error probability are derived for amplify‐and‐forward multihop relay network. Based on approximation of multihop relay by dual‐hop relay systems, the analytical expressions are obtained for the case when maximal ratio combining technique is employed at each relay while destination node uses selection combining technique. The impact of system and channel parameters on the system performances is investigated, and numerical results are graphically presented. The derived analytical expressions are verified by numerical simulation. [ABSTRACT FROM AUTHOR]

Summary: The average symbol error probability (ASEP) performance over the faded radio frequency (RF) link when the noise is additive in nature and has generalized Laplacian distribution is evaluated in this paper. The additive white generalized Laplacian noise (AWGLN) distribution can model different impulsive and non‐Gaussian noise environments often encountered in practice and provides a robust alternative to Gaussian distribution. A new expression for evaluating the exact symbol error probability over a multilevel M‐ary PSK‐modulated AWGLN channel is derived. Based on the obtained expression, the ASEP for the single‐hop RF link that models the shadowing and fading conditions over the RF channel by a generalized –K (GK) distribution is derived. Further, the error performance of a decode‐and‐forward relayed and GK‐distributed two‐hop RF link is discussed, and the results are validated through numerical plots. [ABSTRACT FROM AUTHOR]

Summary: Worldwide Interoperability for Microwave Access (WiMAX) is the broadband wireless access technique that provides rapid broadband services to domestic and enterprise users. Owing to the broadcast characteristic of the WiMAX system, transmitted data security is crucial, particularly when the messages are confidential. In this work, exploiting of WiMAX to convey sensitive secret information is presented. In the first phase, we exploited conventional WiMAX (fast Fourier transform [FFT]‐WiMAX), and in the second phase, we propose a wavelet packet transform (WPT)–based WiMAX for covert communication. The quality evaluation of both covert transmission models (FFT‐WiMAX and WPT‐WiMAX) over the fading channel is done in this work. The experimental outcomes of the proposed WPT‐WiMAX covert transmission system reveal a significant enhancement in error rate (bit error rate) and peak signal‐to‐noise ratio for a given signal‐to‐noise ratio. [ABSTRACT FROM AUTHOR]

Summary: Spatial modulation techniques (SMTs) have emerged as promising multiple‐input and multiple‐output (MIMO) technology for fifth generation (5G) networks, which can achieve an appealing trade‐off between conflicting design objectives such as reliability, hardware cost, complexity, spectral efficiency, and energy efficiency. Most of the SMTs suffer from significant performance deterioration under correlated fading channels. In this paper, a novel spectral efficient SMT referred as enhanced redesigned spatial modulation (EReSM) is proposed, which is robust against adverse channel correlation effects. At any time instant, EReSM activates either one or two transmit antennas and employs a robust bits to antenna index mapping that ensures the selection of antenna subsets with maximum spatial separation to mitigate the effect of spatial correlation. EReSM also exploits phase rotation of transmitted symbols as an additional dimension to convey an extra information bit. The rotation angles used for bit mapping are optimized for various modulation schemes to maximize the minimum euclidean distance between the symbols. To analyze the performance, analytical upper bound expression for average bit error probability (ABEP) is derived for both uncorrelated and spatially correlated channel conditions. Monte Carlo simulation results substantiate the accuracy of the analytical results and also demonstrate that the proposed EReSM outperform conventional redesigned spatial modulation (ReSM) by at least 4 dB. [ABSTRACT FROM AUTHOR]

The field of digital and data communications is becoming increasingly dominant because digital transmission offers data processing options and flexibilities not available with analog transmission. The main feature of a digital communication system is that during a finite interval of time, it sends a waveform from a finite set of possible waveform. One of the most important and fundamental models of communications channels is the binary symmetric channel (BSC). An important measure of system performance in a digital communication system is the probability of error. In this paper, the probability of error, the reliability, the entropy and the channel capacity of a BSC model are studied under non-Gaussian noise disturbances. Namely, Cauchy, Laplace and logistic distributions are considered. It is found that the reliability of the signaling system is low under non-Gaussian noise distributions compared to the Gaussian noise distribution. Several methods were used to reduce the error probability. The amount of improvement in reliability using the reduction methods is higher in the case of Gaussian noise. In order to achieve high reliability under non-Gaussian noise distribution, it is required to increase signal-to-noise ratio (SNR) and increase number of repetitions when sending the same signal different times. Finally, it is observed that increasing the reliability for Cauchy distribution noise has totally failed based on sending the same signal different times and summing the received signals. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Summary: Outage analysis plays a vital role in wireless systems to determine reliable transmission and effective communication. Incremental hybrid decode‐amplify‐forward (IHDAF) relay offers a way of meeting the challenges of capacity and coverage improvement with great potential in cooperative communication networks. Therefore, opportunistic incremental hybrid relaying must be integrated with coding schemes to achieve full diversity. In this paper, the outage behavior of polar coded and distributed coded cooperative relaying schemes is analyzed. Simulation results show that opportunistic incremental HDAF using polar code offers an outage capacity of 17 b/s/Hz for 4 × 4 multiantenna and 45 b/s/Hz in 8 × 8 multiantenna systems with an outage of 10−8 and 10−13, respectively. Moreover, the polar coded opportunistic IHDAF system in 8 × 8 MIMO achieves 2 and 6 dB higher gains compared with amplify‐and‐forward (AF) and decode‐and‐forward (DF) relaying schemes. The closed‐form expression for outage probability has been derived through Marcum‐Q approximations and processed through Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Summary: One of the main challenges of spectrum sensing (SS) in the cognitive radio network (CRN) is selection of threshold for captivating the sensing decision, and such an issue becomes more challenging especially at low signal‐to‐noise ratio (SNR) because it affects the sensing performance and throughput of cognitive user (CU). However, the sensing decision of individual CU may not be accurate due to fading effects in the sensing environment, and significant improvement is accomplished with the cooperation of users. Therefore, in this paper, we have investigated the performance of energy detector SS (EDSS) technique in the CRN under fading environment with cooperative and noncooperative SS scenario. Further, we have introduced the concept of critical SNR (γc) to select the appropriate threshold and based on which the algorithms are proposed to enhance the throughput and reduce the total error (sensing error) probability of CU at different SNR (γ). From the results, we have accomplished that at the low SNR region (γ ≤ γc), throughput is maximum with constant false‐alarm rate (CFAR) threshold selection approach in the cooperative scenario while in the high SNR region (γ> γc), its value is maximum with minimizing the error probability (MEP) threshold selection approach in the noncooperative scenario. Moreover, the sensing error is reduced with cooperation, and threshold selection with MEP approach outperforms CFAR approach for γ ≤ γc. Further, the proposed approach outperforms the other approaches in terms of throughput and sensing error (total error) probability in the Rayleigh and Nakagami‐m fading environments. [ABSTRACT FROM AUTHOR]

Summary: Spatial modulation (SM) is a relatively recent multiple‐input multiple‐output (MIMO) system in which information is carried by the index of the antenna used for transmission as well as by the conventional signal symbols. Several systems that build upon SM have since been proposed including the generalized SM (GSM), a variant of GSM with multiple active antennas (MA‐SM), quadrature SM (QSM), and parallel SM (PSM), among others. The PSM system can increase the spectral efficiency by splitting the antenna set into groups and applying SM independently in each group using the same signal symbol. In this paper, we first derive the upper bound on the error probability of the PSM. The search of the optimal constellation set is then formulated as a multi‐objective optimization problem, where the obtained constellation minimizes the asymptotic error probability. We conclude that as the number of antenna groups increases, the proposed constellation converges to the conventional phase‐shift keying at relatively low number of transmit antennas. The simulation results show that the proposed constellation outperforms conventional constellations by as much as 5 dB, for high‐modulation orders. Since the multi‐objective optimization is independent of the channel matrix, it can be easily done off‐line. This implies that these gains come at no complexity or delay cost. [ABSTRACT FROM AUTHOR]

Summary: The fading channels often involve complex expressions, when it comes to computing the integrals required for performance evaluation of various digital modulation schemes. In this paper, usefulness of exponential‐based approximations to the Gaussian‐Q function in computing these integrals is discussed. We present generic symbol error probability (SEP) expressions over η−μ and κ−μ fading distributions, which can be tailored for any digital modulation technique using different approximations. The resulting expressions thus obtained comprise only elementary mathematical functions thereby avoiding complex evaluations of hypergeometric functions. We explore all the exponential‐based approximations proposed till date and conclude that apart from being mathematically simple, they also lead to accurate expressions for performance analysis of various digital modulation schemes. [ABSTRACT FROM AUTHOR]

Summary: In this paper, we present an analytical framework to analyse the error probability and the channel capacity of the inverse gamma (I‐Gamma) shadowed fading channel. First, the work discusses the utility of the I‐Gamma over log‐normal (LN) and gamma fading models where the closeness of I‐Gamma with other existing shadowing models is carried out. Utilising the probability density function (PDF) of the I‐Gamma shadowed fading channel, various metrics of the communication system, namely, the average symbol error probability (SEP), the channel capacity under optimal rate adaptation (ORA), channel inversion with fixed rate (CIFR), and truncated CIFR (TIFR) are derived. Further, the work is extended to derive a novel selection combining (SC) PDF, and the analytical results for the SEP and the channel capacity of SC diversity are presented. Furthermore, we also provide simpler asymptotic expressions for the average SEP. In addition, the simplified high and low signal‐to‐noise‐ratio (SNR) solutions to channel capacity are also provided. The derived mathematical formulations have been endorsed by comparing with Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

Summary: Finite‐state Markov channels (FSMCs) are widely employed to model the memory of time‐correlated discrete fading channels (DFCs). This work proposes a special class of FSMCs, denoted birth‐death channels (BDCs), to model the statistical behavior of the DFC. The number of states that generates accurate BDCs is estimated for a broad range of fading environments. Next, we evaluate the performance of error‐correcting codes over the BDC. A statistic of interest for this analysis is the P(m,n), the probability the channel generates up to m errors in a block of length n. It also proposed a combinatorial method to evaluate the probability P(m,n) for the BDC. The study of the statistical description of this channels has applications in modeling real channels and in designing coded systems for channels with memory. [ABSTRACT FROM AUTHOR]

Summary: The diversity space of multicarrier continuous‐variable quantum key distribution (CVQKD) is defined. The diversity space utilizes the resources that are injected into the transmission by the additional degrees of freedom of the multicarrier modulation. We prove that the exploitable extra degree of freedom in a multicarrier CVQKD scenario significantly extends the possibilities of single‐carrier CVQKD. The manifold extraction allows for the parties to reach decreased error probabilities by utilizing those extra resources of a multicarrier transmission that are not available in a single‐carrier CVQKD setting. We define the multidimensional manifold space of multicarrier CVQKD and the optimal tradeoff between the available degrees of freedom of the multicarrier transmission. We extend the manifold extraction for the multiple‐access AMQD‐MQA (multiuser quadrature allocation) multicarrier protocol. The additional resources of multicarrier CVQKD allow the achievement of significant performance improvements that are particularly crucial in an experimental scenario. [ABSTRACT FROM AUTHOR]

Summary: The Alamouti space‐time block code (STBC) achieves full diversity gain at a rate of 1/2. However, the Alamouti scheme does not provide multiplexing gain. The Silver code offers both diversity and multiplexing gain. It has a minimum normalization determinant of 1/7. The Golden code is another STBC that offers both diversity and multiplexing gain. The Golden code is ranked higher than the Silver code because of its lower minimum normalization determinant of 1/5, however, the golden code suffers from a high detection complexity in the modulation order of M4. The 3/4‐Sezginer code is another STBC, which compromises between the Alamouti scheme and the Golden code in terms of diversity gain and multiplexing gain. The 3/4‐Sezginer code achieves full diversity and half of multiplexing gain. The uncoded space‐time labeling diversity (USTLD) is a recent scheme that improves the error performance when applied to the STBC in multiple‐input multiple‐output (MIMO) systems and will be applied to the 3/4‐Sezginer STBC to improve the error performance in this paper. The theoretical error probability for both the 3/4‐Sezginer STBC and the improved system is formulated using the union bound in this paper. The theoretical error probabilities of both 16‐QAM and 64‐QAM are validated through Monte Carlo simulation. The simulation and theoretical results show that the proposed system with 4 NR can achieve an SNR gain of 1 dB for 16‐QAM and 1.2 dB 64‐QAM at a bit error rate (BER) of 10−6. [ABSTRACT FROM AUTHOR]

Summary: Multiplicative fading statistics usually encountered in different radio propagation environments. In this context, we evaluate and analyse the performance of a wireless communication system over the nonidentical cascaded generalised Gamma Fading Channels, also known as generalised Bessel‐K fading channel. To this end, the closed‐form expressions for the amount of fading (AOF), the outage probability (OP), the average symbol error probability (SEP), and the channel capacity are derived. In addition approximate expressions for the average SEP with maximal ratio combining (MRC) diversity are also provided. The low‐ and high‐power solutions for the channel capacity are also provided. Furthermore, simplified asymptotic average SEP expressions for MRC and selection combining (SC) are presented to gain the system performance with diversity. The proposed methodologies provide more flexibility to accommodate different radio propagation scenarios. To examine the accuracy of the proposed solutions, numerical and simulation results are compared and shown to fit for variety of fading parameters. [ABSTRACT FROM AUTHOR]

Summary: Quadrature space shift keying (QSSK) modulation combined with cooperative relaying improves the reliability in communication and enhances the overall spectral efficiency. Here, QSSK scheme is analyzed for multiple‐input multiple‐output (MIMO) wireless communication system with dual‐hop amplify‐and‐forward (AF) relaying systems over asymmetric mixed Rayleigh/Rician and symmetric Nakagami‐m/Nakagami‐m fading channels. Analytical expressions for cumulative distribution function (CDF) of the end‐to‐end signal‐to‐noise ratio are derived and used to evaluate the average bit error probability (ABEP) of QSSK modulation in mixed asymmetric and symmetric fading channels. The obtained ABEP expression is in the form of Whittaker function, which can be numerically evaluated using its numerical or series representation. Numerical and simulation results are presented to illustrate the impact of fading parameters on the system performance. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new and exact expression for the bit error probability (BEP) of the square M‐ary quadrature amplitude modulation (M‐QAM) scheme, with the channel under double gated additive white Gaussian noise (G2AWGN) and η‐μ fading in a communication system using the spatial diversity technique. The expression for the BEP is written in terms of the Appell function. The BEP curves are presented under different values of the number of branches of the maximum ratio combining (MRC) receiver, order of the constellation M, and parameters that characterize mathematically the channel, corroborated by simulations performed with Monte Carlo method. [ABSTRACT FROM AUTHOR]

Summary: The Golden code has full rate and full diversity. The Golden codeword matrix contains two pairs of super symbols. Based on one pair of super symbols, two modulation schemes, Golden codeword–based M‐ary quadrature amplitude modulation (GC‐MQAM) and component‐interleaved GC‐MQAM (CI‐GC‐MQAM), are proposed for single‐input multiple‐output (SIMO) systems. Since the complexities of the maximum likelihood detection for the proposed GC‐MQAM and CI‐GC‐MQAM are proportional to O(M2) and O(M4), respectively, low complexity detection schemes for the proposed GC‐MQAM and CI‐GC‐MQAM are further proposed. In addition, the theoretical average bit error probabilities (ABEPs) for the proposed GC‐MQAM and CI‐GC‐MQAM are derived. The derived ABEPs are validated through Monte Carlo simulations. Simulation and theoretical results show that the proposed GC‐MQAM can achieve the error performance of signal space diversity. Simulation and theoretical results further show that the proposed CI‐GC‐16QAM, ‐64QAM, and ‐256QAM with three receive antennas can achieve approximately 2.2, 2.0, and 2.1 dB gain at a bit error rate of 4 × 10−6 compared with GC‐16QAM, ‐64QAM, and ‐256QAM, respectively. [ABSTRACT FROM AUTHOR]