This paper presents a receiving scheme intended to combat the detrimental effects of intersymbol interference for digital transmissions protected by convolutional codes. The receiver performs two successive soft‐output decisions, achieved by a symbol detector and a channel decoder, through an iterative process. At each iteration, extrinsic information is extracted from the detection and decoding steps and is then used at the next iteration as in turbo‐decoding. From the implementation point of view, the receiver can be structured in a modular way and its performance, in bit error rate terms, is directly related to the number of modules used. Simulation results are presented for transmissions on Gauss and Rayleigh channels. The results obtained show that turbo‐equalization manages to overcome multipath effects, totally on Gauss channels, and partially but still satisfactorily on Rayleigh channels.

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The original turbo codes (TCs), presented in 1993 by Berrou et al., consist of the parallel concatenation of two rate-1/2 binary recursive systematic convolutional (RSC) codes. This paper explains how replacing rate-1/2 binary component codes by rate-(+ 1) binary RSC codes can lead to better global performance. The encoding scheme can be designed so that decoding can be achieved closer to the theoretical limit, while showing better performance in the region of low error rates. These results are illustrated with some examples based on double-binary (= 2) 8-state and 16-state TCs, easily adaptable to a large range of data block sizes and coding rates. The double-binary 8-state code has already been adopted in several telecommunication standards.

This paper investigates a new strategy for radio resource allocation applying a non-orthogonal multiple access (NOMA) scheme. It calls for the cohabitation of users in the power domain at the transmitter side and for successive interference canceller (SIC) at the receiver side. Taking into account multi-user scheduling, subband assignment and transmit power allocation, a hybrid NOMA scheme is introduced. Adaptive switching to orthogonal signaling (OS) is performed whenever the non-orthogonal cohabitation in the power domain does not improve the achieved data rate per subband. In addition, a new power allocation technique based on waterfilling is introduced to improve the total achieved system throughput. We show that the proposed strategy for resource allocation improves both the spectral efficiency and the cell-edge user throughput. It also proves to be robust in the case of communications in crowded areas.Index terms -non-orthogonal multiple access, power domain multiplexing, waterfilling, resource allocation.

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This tutorial paper gives an overview of the implementation aspects related to turbo decoders, where the term turbo generally refers to iterative decoders intended for Parallel Concatenated Convolutional Codes as well as for Serial Concatenated Convolutional Codes. We start by considering the general structure of iterative decoders, and the main features of the SISO algorithm that forms the heart of iterative decoders. Then, we show that very efficient parallel architectures are available for all types of turbo decoders allowing high speed implementations. Other implementation aspects like quantization issues and stopping rules used in conjunction with buffering for increasing throughput are considered. Finally, we perform an evaluation of the complexities of the turbo decoders as a function of the main parameters of the code.

FOBTV-13-01 1Abstract-This paper reviews the main technical solutions adopted by the next generation mobile broadcasting standard DVB-NGH, the handheld evolution of the second generation digital terrestrial TV standard DVB-T2. The main new technical elements introduced with respect to DVB-T2 are: layered video coding with multiple physical layer pipes, time-frequency slicing, full support of an IP transport layer with a dedicated protocol stack, header compression mechanisms for both IP and MPEG-2 TS packets, new LDPC coding rates for the data path (down to 1/5), non-uniform constellations for 64QAM and 256QAM, fourdimensional rotated constellations for QPSK, improved time interleaving in terms of zapping time, end-to-end latency and memory consumption, improved physical layer signaling in terms of robustness, capacity and overhead, a novel distributed MISO transmit diversity scheme for SFNs, and efficient provisioning of local content in SFNs. All these technological solutions, together with the high performance of DVB-T2, make DVB-NGH a real next-generation mobile multimedia broadcasting technology. In fact, DVB-NGH can be regarded the first third-generation broadcasting system because it allows for the possibility of using multiple input multiple output MIMO antenna schemes to overcome the Shannon limit of single antenna wireless communications. Furthermore, DVB-NGH also allows the deployment of an optional satellite component forming a hybrid terrestrial-satellite network topology to improve the coverage in rural areas where the installation of terrestrial networks could be uneconomical. to Handheld) [4], were developed to support large scale consumption of mass multimedia services such as mobile television (TV). However, the adoption of mobile TV services did not fulfill the initial expectations due to the lack of a successful business model and the high costs associated to the deployment of new mobile broadcasting networks. Today, a new generation of mobile broadcasting technologies is emerging due to the continuously increasing requirements and expectations of both users and operators, incorporating the latest advances in wireless communications which provide significant capacity and coverage performance improvements compared to first generation mobile broadcast systems. IndexDVB-NGH (Next Generation Handheld) [5] is the handheld evolution of DVB-T2 (Terrestrial 2nd Generation) [6], the most advanced digital terrestrial TV (DTT) technology in the world, offering more robustness, flexibility and at least 50% more spectrum efficiency than any other technology [7].DVB-NGH was created with the objective of becoming the reference mobile multimedia broadcasting standard. However, DVB-NGH not only succeeds significantly outperforming existing mobile broadcasting technologies in terms of capacity and coverage, but also optimizing DVB-T2 in many aspects. Furthermore, DVB-NGH is the first broadcasting system to incorporate Multiple-Input Multiple-Output (MIMO) antenna schemes as the key technology to overcome the S...

This paper introduces new approaches for combining non-orthogonal multiple access with distributed antenna systems. The study targets a minimization of the total transmit power in each cell, under user rate and power multiplexing constraints. Several new suboptimal power allocation techniques are proposed. They are shown to yield very close performance to an optimal power allocation scheme. Also, a new approach based on mutual successive interference cancellation of paired users is proposed. Different techniques are designed for the joint allocation of subcarriers, antennas, and power, with a particular care given to maintain a moderate complexity. The coupling of non-orthogonal multiple access to distributed antenna systems is shown to greatly outperform any other combination of orthogonal/non-orthogonal multiple access schemes with distributed or centralized deployment scenarios.