A novel data stream selection algorithm for S-PARC in TD-SCDMA HSPA+system

In this work, we apply the idea of random phase rotation of the modulated symbols to a system with interfering transmitters and a Maximum-likelihood (ML) receiver. Expressions for Bit Error Rate (BER) for a given channel realization and the average Block Error Rate (BLER) for an error correcting code are derived for the Hard-Decision based ML receiver (HDML). The derived expressions are verified through simulation results and it is observed that at high signal to noise ratio (SNR), when the channel is quasi-static (block fading), random phase rotation provides a gain in BLER when compared to the case without random phase rotation. Also it is observed that the BLER for a system with random phase rotation approaches the BLER for the case of no co-channel interference. The gain due to random phase rotation is also verified for an LTE framework with Soft-Decision based ML receiver (SD-ML).

NOMA-based UAV system under finite blocklength regime with analysis in Rician fading channel

A two-user downlink cooperative non-orthogonal multiple access (NOMA) short-packet communication network is investigated in flat Rayleigh fading channels, where a central user cooperatively relays the signals intended to a cell-edge user. To derive the average block error rate (BLER) of the central user, unlike the work in the literature where the product term is neglected, a new method that works well for the whole range of power allocation factor is proposed. Furthermore, the average BLER of the cell-edge user is theoretically derived. Numerical results demonstrate that while remaining almost the same average BLER for the central user, the cell-edge user in our proposed cooperative NOMA network achieves lower average BLER than those in the conventional NOMA network and the cooperative orthogonal multiple access network.

Recently, ultra-reliable and low-latency communications (URLLC) using short-packets has been proposed to fulfill the stringent requirements regarding reliability and latency of emerging applications in 5G and beyond networks. In addition, multiple-input multiple-output non-orthogonal multiple access (MIMO NOMA) is a potential candidate to improve the spectral efficiency, reliability, latency, and connectivity of wireless systems. In this paper, we investigate short-packet communications (SPC) in a multiuser downlink MIMO NOMA system over Nakagami- m fading, and propose two antenna-user selection methods considering two clusters of users having different priority levels. In contrast to the widely-used long data-packet assumption, the SPC analysis requires the redesign of the communication protocols and novel performance metrics. Given this context, we analyze the SPC performance of MIMO NOMA systems using the average block error rate (BLER) and minimum blocklength, instead of the conventional metrics such as ergodic capacity and outage capacity. More specifically, to characterize the system performance regarding SPC, asymptotic (in the high signal-to-noise ratio regime) and approximate closed-form expressions of the average BLER at the users are derived. Based on the asymptotic behavior of the average BLER, an analysis of the diversity order, minimum blocklength, and optimal power allocation is carried out. The achieved results show that MIMO NOMA can serve multiple users simultaneously using a smaller blocklength compared with MIMO OMA, thus demonstrating the benefits of MIMO NOMA for SPC in minimizing the transmission latency. Furthermore, our results indicate that the proposed methods not only improve the BLER performance, but also guarantee full diversity gains for the respective users.

In this chapter, an effective blind source separation (BSS) algorithm is applied to solve the co-channel interference problem in wireless communication systems. Algorithms developed for this purpose must not only have the capability of working in the complex domain and improving output signal to interference plus noise ratio (SINR), but also have relatively low computational complexity. We propose a fast Fourier transform (FFT)-based algorithm called feedback independent component analysis (FebICA) that is able to blindly separate complex modulated digital signals. By applying this algorithm to communication signals, it is observed that it has the advantages of SINR gain improvement as well as low computational complexity. The performance of the FebICA algorithm is shown to be better than the joint approximate diagonalization of eigen-matrices (JADE) algorithm in terms of the output SINR and requires lower computational complexity than the analytical constant modulus algorithm (ACMA). The algorithm is also shown to be more robust with increasing number of sources compared to other algorithms. The separation performance by using the collected field data has also been demonstrated.

In recent years, the number of Internet of Things (IoT) devices has been increasing. There is a growing demand for communications with high frequency utilization efficiency. Non-orthogonal multiple access (NOMA) is a promising scheme for realizing it. In this paper, we conduct evaluations in power domain NOMA in uplink channel (UL-PD-NOMA) using not only computer simulation but hardware experiment. In our simulations, four user equipments (UEs) send signals simultaneously. These UEs are assigned to the same time and frequency resource. To exploit the diversity effect of frequency selective fading, we propose repetition with cyclic frequency diversity (CFD) that is applied to UL-PD-NOMA system. The number of repetition transmission is set to two for any UE in the paper. At the BS, minimum mean square error based frequency domain equalization (MMSE-FDE) and successive interference cancellation (SIC) are performed to separate superimposed signals. As a result, at a carrier-to-noise ratio of 25 dB, the average block error rate (BLER) of four UEs is improved from 29.6% to 4.4% by using the proposed method in the hardware experiment. And we confirm that the repetition with CFD is effective to improve BLER in UL-PD-NOMA.

In this letter, we propose a downlink nonorthogonal multiple access network with hybrid long-packet communications (for a central user) and short-packet communications (for a cell-edge user). The outage probability of the central user and average block error rate (BLER) of the cell-edge user in flat Rayleigh fading channels are theoretically derived. Furthermore, we provide the asymptotic outage probability and average BLER when the signal-to-noise ratio (SNR) is high. Numerical results illustrate that both the analytical outage probability of the central user and the analytical average BLER of the cell-edge user match the simulation results.

This paper proposes likelihood function generation of complexity-reduced maximum likelihood detection with QR decomposition and M-algorithm (QRM-MLD) suitable for soft-decision turbo decoding and investigates the throughput performance using QRM-MLD with the proposed likelihood function in multipath Rayleigh fading channels for orthogonal frequency and code division multiplexing (OFCDM) with multiple-input multiple-output (MIMO) multiplexing. Simulation results show that by using the proposed likelihood function generation scheme for soft-decision turbo decoding following QRM-MLD in 4-by-4 MIMO multiplexing, the required average received signal energy per bit-to-noise power spectrum density ratio (E/sub b//N/sub o/) at the average block error rate (BLER) of 10/sup -2/ at a 1-Gbps data rate is significantly reduced compared to that using hard-decision decoding in OFCDM access with 16 QAM modulation, the coding rate of 8/9, and 8-code multiplexing with a spreading factor of 8 assuming a 100-MHz bandwidth. Furthermore, we show that by employing QRM-MLD associated with soft-decision turbo decoding for 4-by-4 MIMO multiplexing, the throughput values of 500 Mbps and 1 Gbps are achieved at the average received E/sub b//N/sub o/ of approximately 4.5 and 9.3 dB by QPSK with the coding rate of R = 8/9 and 16 QAM with R = 8/9, respectively, for OFCDM access assuming a 100-MHz bandwidth in a twelve-path Rayleigh fading channel.

Signal to interference plus noise ratio (SINR) based call admission control (CAC) scheme admits incoming calls as long as the measured SINR is higher than threshold value (SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> ). If a high value of SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> is chosen, the signal quality will improve but this will increase the blocking probability (p <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> ), and as a result, will decrease the network utilization. On the other hand, a low value of SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> will reduce p <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> , however degrades the signal quality and increases outage probability (p <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</sub> ). Hence, how to choose appropriate SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> is very important. In this paper, we focus on the following aspects. Firstly, an accurate upper bound of SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> is derived. Secondly, based on the upper bound of SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> and a lower bound from other literature, we design a fuzzy logic controller (FLC), which can adaptively adjust SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> according to the number of active users (AUs) in a cell and average arriving traffic intensity (AATI) in Erlang per cell. Finally, network performance based on FLC is compared with that based on optimal fixed SINR <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> . Numerical results show that the proposed scheme based on FLC has better performance than the optimal fixed threshold CAC scheme.

The fifth generation (5G) wireless networks are expected to provide a wide range of time-sensitive multimedia services and applications to satisfy users' stringent requirements on delay-bounded quality of service (QoS). Finite blocklength coding theory can efficiently address the issue of delay-bounded QoS constraint guarantees, where mobile users send messages using packets with small numbers of bits to achieve low latency transmissions. In this paper, we employ the Nakagami-m fading model to analyze channel coding performance in the finite blocklength regime, in terms of average block error rate, capacity outage probability, and symbol error probability. We first derive closed-form expressions for upper and lower bounds on the average block error rate. Then, we compare these bounds with the capacity outage probability and show that the average block error rate is larger than the capacity outage probability. We also obtain a lower-bound in closed-form for the symbol error probability under M-ary phase shift keying (MPSK). Finally, we validate and evaluate our derived average block error rate bound, capacity outage probability, and symbol error probability in the finite blocklength regime through numerical analyses.

A heterogeneous network (HetNet) that consists of various wireless networks is being massively studied. Integration of the networks should be error free to achieve seamless communication. The seamless vertical handoff (VHO) remains a challenging problem in HetNet studies. Several criteria for VHO decision have been studied in the literature, such as Received Signal Strength (RSS) and Signal to Interference plus Noise Ratio (SINR). It has been shown that SINR based VHO has superior performance compare to RSS based VHO. However, there are some limitations in SINR based VHO scheme. This study aims to overcome those limitations by considering user velocity as an additional criterion for SINR based VHO decision. User velocity is represented in the value of additional SINR threshold. The basic principle of the proposed algorithm is that slow speed user should stay longer in WLAN cells and high speed user should stay longer in WCDMA cells. Simulation results show that there is a trade-off between average throughput and the number of unnecessary handoffs per call. In this study, optimum threshold is obtained when the high percentage of unnecessary handoffs reduction is reached with an acceptable value of average throughput for multimedia data transfer.

The aim of this paper is to present a non‐linear statistical model to fit and forecast the signal‐to‐interference plus noise ratio (SINR) in two‐tier heterogeneous cellular networks which consist of macrocells and femtocells. Since in these networks the number and locations of femtocell base stations (FBS) are variable, SINR forecasting can be useful in some areas such as power control and handover management. So far, linear autoregressive (AR) models have commonly been used in forecasting the received signal strength (rss) in macrocellular networks. However, AR modelling results in high mean square error (MSE) when data are non‐linear. This paper focuses on SINR which takes into account signal strength, interference and noise effects. Moreover, macro‐femto cellular network is considered. The F ‐test results show that the SINR data are non‐linear, leading to use non‐linear models instead of AR model. A non‐linear logistic smooth threshold AR (LSTAR) model is utilised to model and forecast the SINR data. Kolmogorov–Smirnov (K‐S) test demonstrates that LSTAR provides good fitness to the SINR samples. The results indicate that LSTAR model achieves much better performance in modelling and forecasting of SINR data than the AR model.

Single carrier frequency division multiple access (SC-FDMA) has been adopted as uplink multiple access scheme for 3GPP LTE as it combines the advantages of orthogonal frequency division multiple access (OFDMA) and the low envelope variation properties of single carrier (SC) transmission. Moreover, the classical transmit antenna diversity technique as space-time block code (STBC) and space-frequency block code (SFBC) can improve the uplink performance combination with SC-FDMA schemes. In this paper, a signal-to-interference-plus-noise ratio (SINR) performance analysis method of SC-FDMA is proposed for STBC and SFBC schemes, respectively. The closed-form SINR expressions based on the modified SC-preserved implementation structure and MMSE equalization for receivers are derived by channel frequency response and noise variance, considering inter-symbol interference. Moreover, it can be easily extended to multi-receive antennas. By simulation results it is shown that with proposed equivalent SINR, the BLock Error Rate (BLER) performance of MIMO-SC-FDMA over slow fading channel is well matched with that over AWGN channel.

A comprehensive reference book codifying the various standards releases for High Speed Packet Access (HSPA) wireless technologyHSPA evolution has maintained its prominence through Releases 7-11 but the evolution is coming to an end with Release 12, with the focus moving to LTE. However, HSPA network and terminal sales will continue for many years: HSPA is expected to remain as the number one radio access technology from the sales point of view far beyond 2015. This timely book examines the complete HSPA evolution, and will be the ultimate long term reference for HSPA evolution.Headed by the successful editing team of Holma, Toskala and Tapia, industry experts look at HSPA evolution including complete Release 11 and the main additions in Release 12. They describe 3GPP definitions, field measurement, expected performance, practical optimization guidelines and the implications to the devices and to the networks. The book also covers MIMO antenna solutions and multicarrier evolution to provide higher data rates. Dedicated chapters include Continuous Packet Connectivity and High Speed Common Channels which provide major improvement to the smartphone capacity, end user performance and power consumption. The book assumes basic understanding of mobile communications yet the material is presented in an understandable way which can be enjoyed without any pre-information about MIMO or other technology solutions.A comprehensive reference book codifying the various standards releases for High Speed Packet Access (HSPA) wireless technologyLeading editor and contributor team focusing their expertise on 3GPP features and performance, including Self Organizing Networks, LTE Interworking, Smartphone Optimization and Voice EvolutionDedicated chapter covering VoIP over HSPA, recognizing that telephony will continue to bring most of the revenues to mobile operators in the near futureIncludes tables, figures and plots illustrating the concepts or simulation results, to aid readers understanding of the topicAn essential resource for R&D engineers by network, terminal and chip set vendors, network engineers with operators, application developers, regulators.

We consider the downlink of a multiple-input multiple-output broadcast channel where the transmitter uses per user unitary and rate control (PU2RC) to perform the user scheduling and beamforming. The main shortcoming of the PU2RC scheme is in networks where the number of users is less than or comparable with the codebook size. In these networks, PU2RC cannot properly exploit the available channel dimensions. To deal with this problem, they propose two different approaches to enhance the throughput performance of the system. In the first approach, they try to find and assign unscheduled users to the unused channel dimensions. This is done through a signal-to-interference plus noise ratio (SINR) estimation method in which they approximate the SINR of the users along new beamforming vectors. In this approach, they usually achieve the maximum multiplexing order of the system. In the second approach, they adjust the SINR feedbacks according to the number of scheduled users. When the number of scheduled users is less than the number of transmitting antennas, the feedback SINRs are in fact underestimated. In this case, they correct the SINRs and improve the average throughput. The simulation results show that both proposed methods can effectively improve the performance of the PU2RC scheme.