We consider the uplink (UL) and downlink (DL) of non-cooperative multi-cellular time-division duplexing (TDD) systems, assuming that number N antennas per base station (BS) K user terminals (UTs) cell are large. Our system model accounts for channel estimation, pilot contamination, an arbitrary path loss antenna correlation each link. derive approximations achievable rates with several linear precoders detectors which proven to be asymptotically tight, but accurate realistic dimensions, as...

Mutual information transfer characteristics of soft in/soft out decoders are proposed as a tool to better understand the convergence behavior iterative decoding schemes. The exchange extrinsic is visualized trajectory in chart (EXIT chart). This allows prediction turbo cliff position and bit error rate after an arbitrary number iterations. influence code memory, polynomials well different constituent codes on studied for parallel concatenated codes. A search based EXIT technique has been...

Recent advancements in iterative processing of channel codes and the development turbo have allowed communications industry to achieve near-capacity on a single-antenna Gaussian or fading with low complexity. We show how these techniques can also be used multiple-antenna system where receiver knows channel. Combining channels is particularly challenging because capacities factor ten more higher than their counterparts. Using "list" version sphere decoder, we provide simple method iteratively...

A coding and modulation technique is studied where the coded bits of an irregular low-density parity-check (LDPC) code are passed directly to a modulator. At receiver, variable nodes LDPC decoder graph connected detector nodes, iterative decoding accomplished by viewing as one decoder. The optimized performing curve fitting on extrinsic information transfer charts. Design examples given for additive white Gaussian noise channels, well multiple-input, multiple-output (MIMO) fading channels...

This article provides some fundamental indications about wireless communications beyond LTE/LTE-A (5G), representing the key findings of European research project 5GNOW. We start with identifying drivers for making transition to 5G networks. Just name one, advent Internet Things and its integration conventional human-initiated transmissions creates a need system redesign. Then we make clear that strict paradigm synchronism orthogonality as applied in LTE prevents efficiency scalability....

End-to-end learning of communications systems is a fascinating novel concept that has so far only been validated by simulations for block-based transmissions. It allows transmitter and receiver implementations as deep neural networks (NNs) are optimized an arbitrary differentiable end-to-end performance metric, e.g., block error rate (BLER). In this paper, we demonstrate over-the-air transmissions possible: We build, train, run complete system solely composed NNs using unsynchronized...

Extrinsic information transfer (EXIT) charts are a tool for predicting the convergence behavior of iterative processors variety communication problems. A model is introduced that applies to decoding problems, including parallel concatenated (turbo) codes, serially low-density parity-check (LDPC) and repeat-accumulate (RA) codes. EXIT functions defined using model, several properties such proved erasure channels. One property expresses area under an function in terms conditional entropy....

A novel method for visualising the convergence behaviour of iterative decoding schemes is proposed. Each constituent decoder represented by a mutual information transfer characteristic which describes flow extrinsic through soft in/soft out decoder. The exchange between decoders plotted in an chart. concepts are illustrated demapping and scheme.

In this paper, we propose a multi-carrier transmission scheme to overcome the problem of intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) systems. proposed scheme, called universal-filtered (UFMC), filtering operation is applied group consecutive subcarriers (e.g. given allocation single user) order reduce out-of-band sidelobe levels and subsequently minimize potential ICI between adjacent users case asynchronous transmissions. We consider coordinated...

We revisit the idea of using deep neural networks for one-shot decoding random and structured codes, such as polar codes. Although it is possible to achieve maximum a posteriori (MAP) bit error rate (BER) performance both code families short codeword lengths, we observe that (i) codes are easier learn (ii) network able generalize codewords has never seen during training structured, but not These results provide some evidence can form algorithm, rather than only simple classifier. introduce...

Iterative decoding algorithms for spectrally efficient modulation have become a vital field of research in digital communications. We show how iterative demapping reduces the bit error rate conventional communication systems applying multilevel combined with simple channel coding. For this soft has to be modified order accept priori information. The system can regarded as serially concatenated scheme whereby inner decoder is replaced by device. A design rule based on mutual information find...

Equipping base stations (BSs) with very large antenna arrays is a promising way to increase the spectral and energy efficiency of mobile communication systems without need for new cell sites. However, prominently theoretical works on this topic are based several crucial assumptions about wireless channel which have not been sufficiently validated by measurements. In paper, we report an outdoor measurement campaign scalable virtual array consisting up 112 elements. The amount acquired data...

We extend the idea of end-to-end learning communications systems through deep neural network (NN)-based autoencoders to orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP). Our implementation has same benefits as a conventional OFDM system, namely single-tap equalization and robustness against sampling synchronization errors, which turned out be one major challenges in previous single-carrier implementations. This enables reliable communication over multipath channels...

We consider a multicell MIMO uplink channel where each base station (BS) is equipped with large number of antennas N. The BSs are assumed to estimate their channels based on pilot sequences sent by the user terminals (UTs). Recent work has shown that, as N → ∞, (i) simplest form detection, i.e., matched filter (MF), becomes optimal, (ii) transmit power per UT can be made arbitrarily small, (iii) system performance limited contamination. aim this paper assess which extent above conclusions...

The training complexity of deep learning-based channel decoders scales exponentially with the codebook size and therefore number information bits. Thus, neural network decoding (NND) is currently only feasible for very short block lengths. In this work, we show that conventional iterative algorithm polar codes can be enhanced when sub-blocks decoder are replaced by (NN) based components. partition encoding graph into smaller train them individually, closely approaching maximum a posteriori...

We consider a trainable point-to-point communication system, where both transmitter and receiver are implemented as neural networks (NNs), demonstrate that training on the bit-wise mutual information (BMI) allows seamless integration with practical bit-metric decoding (BMD) receivers, well joint optimization of constellation shaping labeling. Moreover, we present fully differentiable iterative demapping (IDD) structure which achieves significant gains additive white Gaussian noise (AWGN)...

The "writing on dirty paper"-channel model offers an information-theoretic framework for precoding techniques canceling arbitrary interference known at the transmitter. It indicates that lossless is theoretically possible any signal-to-noise ratio (SNR), and thus dirty-paper coding may serve as a basic building block in both single-user multiuser communication systems. We design end-to-end realization of system materializing significant portion promised gains. employ multidimensional...

Extrinsic information transfer (EXIT) charts are used to design systematic and nonsystematic repeat-accumulate (RA) codes for iterative detection decoding. The convergence problems of RA solved by introducing a biregular, or doped, layer check nodes. As examples, such designed multi-input/multi-output (MIMO) fading channels shown operate close capacity.

In this paper, we present a vision beyond the conventional Long Term Evolution Fourth Generation (LTE-4G) evolution path and suggest that time division duplexing (TDD) could be key enabler for new heterogeneous network architecture with potential to provide ubiquitous coverage unprecedented spectral area efficiencies. This is based on cochannel deployment of macro base stations (BSs) very large antenna arrays secondary tier small cells (SCs) few antennas each. Both tiers employ TDD protocol...

We propose a belief propagation list (BPL) decoder with comparable performance to the successive cancellation (SCL) of polar codes, which already achieves maximum likelihood (ML) bound codes for sufficiently large size $L$. The proposed is composed multiple parallel independent (BP) decoders based on differently permuted code factor graphs. A possible transmitted codewords generated and one closest received vector, in terms Euclidean distance, picked. To best our knowledge, BPL provides...

LTE and LTE-Advanced have been optimized to deliver high bandwidth pipes wireless users. The transport mechanisms tailored maximize single cell performance by enforcing strict synchronism orthogonality within a contiguous frequency band. Various emerging trends reveal major shortcomings of those design criteria: (1) fraction machine-type-communications (MTC) is growing fast. Transmissions this kind are suffering from the bulky procedures necessary ensure synchronism. (2) Collaborative...

We present a new framework for constructing polar codes (i.e., selecting the frozen bit positions) arbitrary channels, tailored to given decoding algorithm rather than assuming (not necessarily optimal) successive cancellation (SC) decoding. The proposed is based on genetic (GenAlg), where populations collections) of information sets evolve via evolutionary transformations their individual error-rate performance. These converge toward an set that fits both behavior and defined channel....

We propose a time division duplex (TDD) based network architecture where macrocell tier with "massive" multiple-input multiple-output (MIMO) base station (BS) is overlaid dense of small cells (SCs). In this context, the TDD protocol and resulting channel reciprocity have two compelling advantages. First, large number BS antennas can be deployed without incurring prohibitive overhead for training. Second, estimate interference covariance matrix from SC which leveraged downlink precoding....

Reed–Muller (RM) codes are known for their good maximum likelihood (ML) performance in the short block-length regime. Despite being one of oldest classes channel codes, finding a low complexity soft-input decoding scheme is still an open problem. In this work, we present versatile architecture RM based on rich automorphism group. The algorithm can be seen as generalization multiple-bases belief propagation (MBBP) and may use any polar or decoder constituent decoders. We provide extensive...

The authors present an iterative decoding scheme which is particularly suited for quadrature phase shift keying (QPSK) modulation with anti-Gray mapping. At the receiver, a soft demapper accepting priori information and convolutional decoder are applied in serial concatenation. Numerical results presented QPSK additive white Gaussian noise Rayleigh-fading channels. iterated system applying mapping outperforms conventional using Gray after only one iteration.