Beam Direction-Based Modulation for Millimeter-Wave Communication Systems: Design and Optimization

Sparse vector coding (SVC) is a promising short-packet transmission method for ultra reliable low latency communication (URLLC) in next generation communication systems. In this paper, a dual-mapping SVC (DM-SVC) based short packet transmission scheme is proposed to further enhance the transmission performance of SVC. The core idea behind the proposed scheme lies in mapping the transmitted information bits onto sparse vectors via block and single-element sparse mappings. The block sparse mapping pattern is able to concentrate the transmit power in a small number of non-zero blocks thus improving the decoding accuracy, while the single-element sparse mapping pattern ensures that the code length does not increase dramatically with the number of transmitted information bits. At the receiver, a two-stage decoding algorithm is proposed to sequentially identify non-zero block indexes and single-element non-zero indexes. Extensive simulation results verify that proposed DM-SVC scheme outperforms the existing SVC schemes in terms of block error rate and spectral efficiency.

The effect of dynamic stimulated Brillouin scattering (SBS) on millimeter-wave fiber radio communication systems has been studied and compared with results by steady-state analysis (SSA). More information is provided by the dynamic SBS analysis as the probability density functions (pdf's) of both SBS power and received signal can be calculated approximately. The worst-case power by SSA overestimates the effect of SBS greatly while the average power by SSA underestimates it. The dynamic SBS analysis, therefore, should be used for estimating the effect of SBS on millimeter-wave fiber radio communication systems, especially for low bit rate and short length ones.

Millimeter wave (MMW) communication is a promising technology to cope up with the ever increasing demand for multi gigabit wireless applications and to alleviate the problems of spectrum scarcity for Fifth generation (5G) mobile communication applications. The coverage distance of the MMW communication system is severely affected due to the various losses such as free space loss, atmospheric loss, and foliage loss. However MMW communication allows the use of smaller antenna size which can facilitate the fabrication of large antenna arrays over small area like a postage stamp which can be used at both transmitter and receiver. This helps in efficient use of the Multi-Input Multi-Output (MIMO) technology in MMW Communication systems which can improve the coverage distance as well as capacity of the system. In this paper, we perform the Mathematical analysis of the coverage distance of MMW communication link and study the effects of different parameters on its performance. A simulation study to examine the effect of the MIMO antenna system for improving the coverage distance of MMW communication links for specific data rates for Line of Sight (LOS) and Non-Line of Sight (NLOS) cases in a highly dense mobile network scenario has been done and results are presented in this paper.

A semiconductor laser diode direct detection optical communication system suitable for use in an intersatellite communication link was constructed, and its performance was measured. The system used Q = 4 pulse position modulation (PPM) to transmit binary source data at a rate of 25 Mbit/s and contained a low-noise silicon avalanche photodiode (APD) as a photodetector. Use of the conventional Gaussian model for the output of the low-noise APD (RCA C30902S) was shown to be inappropriate under low-background radiation levels because its use caused a severe underestimate of the optical APD gain and an overestimate of a system bit error rate. A numerical procedure was developed that made use of the Conradi distribution for the APD output which gave good agreement with the results of the experimental measurements of system performance. A slot clock recovery subsystem was also provided in the receiver. It consisted of a nonlinearity which is easy to implement and a narrow bandpass filter centered at the slot clock frequency. Use of the recovered timing signal showed no penalty in the minimal input optical power required to maintain a specified error rate. The system achieved a bit error rate of 10−6 at a received signal level corresponding to an average of 60 detected photons per transmitted information bit (120 photons per PPM symbol).

In this paper, we study transmit codebook designs for spatial modulation with analog phase shifters. The proposed spatial modulation with analog phase shifters can send more spatial symbols than conventional spatial modulation, while reserving the low complexity of single RF-chain MIMO structure. The main idea is to transmit N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> different phase-shifted copies of a digitally modulated signal through N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> transmit antennas. In each time slot, the transmitted information bits are divided into two groups. The first group of the bits is mapped to the digitally modulated signal symbol. The second group of the bits is mapped to the spatial symbol, which determines the phase shift of each antenna. The transmit signal designs are carried out in open loop and closed loop scenarios, respectively. In open loop scenario, the transmit codebook is designed in two steps, i.e., generate the optimal spatial codebook according to Grassmannian line packing criterion, and find the optimal tradeoff between the cardinality of spatial codebook and the modulation order of signal symbol. In the closed loop scenario, the transmit codebook is designed according to the structure of Huffman tree. Extensive simulation results are given to validate the effectiveness of the proposed scheme in open loop scenario and close loop scenario, respectively.

The conventional matched filter (MF) correlation receiver for direct sequence spread spectrum transmissions is reconsidered from the theoretical point of view of robust distributed detection (decision fusion). Separate chip-by-chip decisions on the transmitted information bit of interest are generated. The individual decisions are then optimally fused to produce the final decision on the transmitted bit. It is proven that the majority-vote strategy is the statistically optimal fusion rule for additive white Gaussian noise channels. An exact closed form expression is given for the probability of error induced by the majority-vote receiver. It is shown that the performance is independent of the identity of the active interfering user population, that is signatures and signature cross-correlations, in DS-CDMA environments. This perfect robustness with respect to the identity of the multiuser interference component is coupled by significant resistance toward occasional high-power jamming (equivalently occasional natural severe channel imperfections) or outlier-prone background noise, or both. Some numerical studies illustrate these theoretical findings.

Transmission efficiency, defined as the ratio of successfully transmitted information bits to overall bits transmitted, can be used for evaluating the transmission performance of wireless links. As a function of received signal to noise ratio (SNR), transmission efficiency is determined by physical layer technologies, such as channel coding, interleaving, modulation and other error-recovery techniques of wireless links. In this paper we first analyze the form of transmission efficiency function in wireless links, then based on that we propose an adaptive coding scheme that maximizes the transmission efficiency according to wireless channel conditions (received SNR). Simulation results show that with the proposed adaptive coding, transmission efficiency of wireless links can be significantly enhanced.

Multiantenna transmission using load modulated arrays (LMAs) is gaining recent research interest. LMAs use a single central power amplifier and tune the antenna loads according to the information signal. In this paper, we propose a novel multiantenna transmitter architecture that can enable high-rate transmissions using LMAs. The proposed architecture uses channel modulation with RF mirrors in conjunction with antenna load modulation to transmit information bits. The proposed architecture has two key advantages: 1) it facilitates simple construction of high-rate signal sets suited for LMAs, and 2) it requires significantly fewer channel coefficients to be estimated at the receiver compared to conventional channel modulation architectures. The proposed architecture is shown to achieve improved bit error performance compared to conventional load modulation as well as spatial modulation, which are also single power amplifier transmission schemes. We also investigate the use of the proposed transmission scheme in a multiuser setting on the uplink. The proposed scheme not only offers the advantage of RF hardware simplicity at the user equipment but also requires fewer receive antennas at the base station to achieve a target bit error performance.

The use of miniaturized biomedical devices implanted in the human body and wirelessly internetworked is promising a significant leap forward in medical treatment of many pervasive diseases. Recognizing the well-understood limitations of traditional radio-frequency wireless communications in interconnecting devices within the human body, in this paper we propose to develop network protocols for implantable devices based on ultrasonic transmissions. We start off by assessing the feasibility of using ultrasonic propagation in human body tissues and by deriving an accurate channel model for ultrasonic intra-body communications. Then, we propose a new ultrasonic transmission and multiple access technique, which we refer to as Ultrasonic WideBand (UsWB). UsWB is based on the idea of transmitting information bits spread over very short pulses following a time-hopping pattern. The short impulse duration results in limited reflection and scattering effects, and its low duty cycle reduces the thermal and mechanical effects, which are detrimental for human health. We then develop a multiple access technique with distributed control to enable efficient simultaneous access by interfering devices based on minimal and localized information exchange and on measurements at the receiver only. Finally, we demonstrate the performance of UsWB through a multi-scale simulator that models the proposed communication system at the acoustic wave level, at the physical (bit) level, and at the network (packet) level.

An adaptive coded modulation (ACM) scheme for a frequency-flat fading channel utilizes a set of channel codes with different spectral efficiencies. A feedback channel between the decoder and encoder makes it possible for the encoder to switch adaptively between these codes based on channel state information (CSI) fed back from the decoder. An orthogonal frequency division multiplexing (OFDM) system may utilize ACM on its subchannels to obtain a large average spectral efficiency (ASE), measured in transmitted information bits per second per unit bandwidth. In this paper we present a new upper bound on the ASE of OFDM/ACM systems. We also discuss how CSI estimation errors will influence the performance of an ACM system, and limit its possible region of operation with regard to channel signal-to-noise ratios and terminal velocities. (5 pages)

Frequency-hopped multiple-access communication systems employing Reed-Solomon (RS) coded M-ary FSK signalling is considered on a Rayleigh fading channel. The authors examine the optimal modulation alphabet size that maximises the average number of successfully transmitted information bits per dimension in connection with the channel traffic, the signal-to-noise ratio, and the required bit error probability.

We design and assess some practical low-density parity-check (LDPC) coded transmission schemes for the Gaussian broadcast channel with confidential messages (BCC). This channel model is different from the classical wiretap channel model as the unauthorized receiver (Eve) must be able to decode some part of the information. Hence, the reliability and security targets are different from those of the wiretap channel. In order to design and assess practical coding schemes, we use the error rate as a metric of the performance achieved by the authorized receiver (Bob) and the unauthorized receiver (Eve). We study the system feasibility, and show that two different levels of protection against noise are required on the public and the secret messages. This can be achieved in two ways: i) by using LDPC codes with unequal error protection (UEP) of the transmitted information bits or ii) by using two classical non-UEP LDPC codes with different rates. We compare these two approaches and show that, for the considered examples, the solution exploiting UEP LDPC codes is more efficient than that using non-UEP LDPC codes.

In this paper, we propose a multi-hop multi-branch multiple-input multiple-output (MIMO) SSK scheme with path selection and investigate its error performance. In this scheme, the best path is selected among multiple branches and a multiple-antenna source (S) communicates with a multiple-antenna destination (D) via the relays of the selected path. Each relay is equipped with multiple transmit and receive antennas. It is assumed that there is no direct link between S and D. Moreover, S and all relays employ SSK modulation to transmit information bits and each relay in each path follows the decode-and-forward principle. A closed-form approximate symbol error rate (SER) expression for the proposed SSK system is derived. Furthermore, an asymptotic SER performance analysis is also performed. The analytical results are verified through Monte Carlo simulations. It is shown that the proposed multi-hop SSK system with path selection outperforms conventional multihop M-PSK system with path selection in terms of the SER performance for especially high data rates and sufficient number of receive antennas at the receiving nodes.

This study introduces a biconvex non-spherical lens horn antenna designed for operation in the millimeterwave frequency range. Significant improvements were achieved by analyzing the phase relationship of the aperture field and iteratively adjusting the lens height. The lens, made of Teflon, serves as the medium in the form of a biconvex non-spherical lens. Through simulation analysis, it was found that the dielectric lens notably reduced the phase error in the antenna aperture field and increased the antenna gain. The antenna gain increased from 27.61 dB to 29.11 dB, with the dielectric lens reducing the antenna's 3 dB beamwidth. In cases where the maximum gain in the E-plane decreased by 3 dB, the sum of the absolute values on both sides decreased from 7.12° to 5.61°, and in the H -plane from 6.66° to 5.72°. The length of the antenna aperture field matches that of a standard horn antenna. Further optimization could lead to its application in millimeter-wave communication systems, demonstrating its significance in millimeter-wave antenna design research.

This paper presents a dual passband frequency selective surface for future 5G communications. The FSS has two ring slots with hexagonal shape, one of which has been applied with a fractal generator. The FSS unit cell is 3.7×3.7mm2. The pass band ranges are 27.639 - 28.997 GHz and 37.442 - 41.452 GHz, covering both 28 and 38 GHz 5G bands. The FSS has been modelled using very thin 0.127 mm flexible Rogers substrate. The dual band response, low cost and unique design makes this FSS suitable for EMI shielding as well as radome applications for future 5G and millimeter-wave communication systems.