Massive multiple-input multiple-output (MIMO) wireless communications refers to the idea equipping cellular base stations (BSs) with a very large number of antennas, and has been shown potentially allow for orders magnitude improvement in spectral energy efficiency using relatively simple (linear) processing. In this paper, we present comprehensive overview state-of-the-art research on topic, which recently attracted considerable attention. We begin an information theoretic analysis...

A Cell-Free Massive MIMO (multiple-input multiple-output) system comprises a very large number of distributed access points (APs), which simultaneously serve much smaller users over the same time/frequency resources based on directly measured channel characteristics. The APs and have only one antenna each. acquire state information through time-division duplex operation reception uplink pilot signals transmitted by users. perform multiplexing/de-multiplexing conjugate beamforming downlink...

This paper considers a multi-cell multiple antenna system with precoding used at the base stations for downlink transmission. Channel state information (CSI) is essential stations. An effective technique obtaining this CSI time-division duplex (TDD) operation where uplink training in conjunction reciprocity simultaneously provides as well channel estimates. mathematically characterizes impact that has on performance of such systems. When non-orthogonal sequences are training, shows matrix by...

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...

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....

Cell-free Massive multiple-input multiple-output (MIMO) comprises a large number of distributed low-cost low-power single antenna access points (APs) connected to network controller. The AP antennas is significantly larger than the users. system not partitioned into cells and each user served by all APs simultaneously. simplest linear precoding schemes are conjugate beamforming zero-forcing. Max-min power control provides equal throughput users considered in this paper. Surprisingly, under...

We define and show how to construct nonbinary quantum stabilizer codes. Our approach is based on error bases. It generalizes the relationship between self-orthogonal codes over F/sub 4/ binary one F(q/sup 2/) q-ary for any prime power q.

In this paper we study the performance of cellular networks when their base stations have an unlimited number antennas. previous work, asymptotic behavior signal to interference plus nose ratio (SINR) was obtained. We revisit these results by deriving rigorous expression for SINR both downlink and uplink in scenario infinite show that contamination channel estimates happens whenever a pilot sequence is received at station simultaneously with non-orthogonal signals coming from other users....

An LSAS entails a large number (tens or hundreds) of base station antennas serving much smaller terminals, with gains in spectral-efficiency and energy-efficiency compared conventional MIMO technology. Until recently it was believed that multi-cellular LSAS, even the asymptotic regime, as service tends to infinity, performance is limited by directed inter-cellular interference. The interference results from unavoidable re-use reverse-link pilot sequences (pilot contamination) terminals...

We consider the downlink of Cell-Free Massive MIMO systems, where a very large number distributed access points (APs) simultaneously serve much smaller users. Each AP uses local channel estimates obtained from received uplink pilots and applies conjugate beamforming to transmit data derive closed-form expression for achievable rate. This enables us design an optimal max-min power control scheme that gives equal quality service all further compare performance system conventional small-cell...

Cell-Free Massive MIMO systems comprise a large number of distributed, low cost, and power access point antennas, connected to network controller. The antennas is significantly larger than the users. system not partitioned into cells each user served by all simultaneously. In this paper, we define cell-free analyze algorithms for optimization linear pre-coding. Compared with conventional small-cell scheme, can yield more ten-fold improvement in terms 5%-outage rate.

Minimal vectors in linear codes arise numerous applications, particularly, constructing decoding algorithms and studying secret sharing schemes. However, properties structure of minimal have been largely unknown. We prove basic general codes. Then we characterize a given weight compute their number several classes codes, including the Hamming second-order Reed-Muller Further, extend concept to over rings them for examples. Turning introduce gradient-like algorithm which minimal-vectors is an...

This paper considers a multi-cell multiple antenna system with precoding at the base stations for downlink transmission. To enable precoding, channel state information (CSI) is obtained via uplink training. mathematically characterizes impact that training has on performance of systems. When non-orthogonal sequences are used training, it shown matrix by station in one cell becomes corrupted between and users other cells. problem pilot contamination analyzed this paper. A MMSE-based proposed...

This paper considers the problem of interference mitigation in multi-cell multi-antenna time division duplex (TDD) wireless systems for downlink transmission. An efficient way to obtain channel state information (CSI) at base station is by using uplink pilots and reciprocity channel. At same time, it has been shown that from different cells contaminate each other, resulting corruption precoding matrices used stations, high inter-cell interference. studies effects shifting location frames...

Cell-Free Massive MIMO comprises a large number of distributed single-antenna access points (APs) serving much smaller users. There is no partitioning into cells and each user served by all APs. In this paper, the uplink performance cell-free systems with minimum mean squared error (MMSE) scale fading decoding (LSFD) receivers investigated. The main idea LSFD receiver to maximize achievable throughput using only coefficients between APs Capacity lower bounds for MMSE are derived. An...

A wireless massive multiple-input multiple-output (MIMO) system entails a large number of base station antennas serving much smaller users, with gains in spectral efficiency and energy compared the conventional MIMO technology. Until recently, it was believed that as tends to infinity, performance such systems is limited by directed inter-cellular interference caused unavoidable re-use training sequences (pilot contamination) users different cells. We devise new concept large-scale fading...

A massive MIMO system entails a large number (tens or hundreds) of base station antennas serving much smaller terminals. These systems demonstrate gains in spectral and energy efficiency compared with the conventional technology. As grows, performance gets limited by interference caused pilot contamination. Ashikhmin Marzetta proposed (under name Pilot Contamination Precoding) scale fading precoding (LSFP) decoding (LSFD) based on cooperation between stations. They showed that zero-forcing...

Linear programming approaches have been applied to derive upper bounds on the size of classical and quantum codes. In this paper, we similar results for general codes with entanglement assistance by considering a type split weight enumerator. After deriving MacWilliams identities these enumerators, are able prove algebraic linear bounds, such as Singleton bound, Hamming first bound. Our bound more than previous entanglement-assisted stabilizer addition, show that improves when relative...

In this article, we propose a wirelessly powered Internet-of-Things (IoT) system based on the cell-free massive MIMO technology. such system, during downlink phase, sensors harvest radio-frequency (RF) energy emitted by distributed access points (APs). During uplink transmit data to APs using harvested energy. Collocated and small-cell IoT can be treated as special cases of IoT. We derive tight closed-form lower bound amount energy, expression SINR metrics power transfer transmission,...

An Internet-of-Things (IoT) system supports a massive number of IoT devices wirelessly. We show how to use cell-free (CF) multiple input and output (MIMO) provide scalable energy-efficient system. employ optimal linear estimation with random pilots acquire channel state information (CSI) for MIMO precoding decoding. In the uplink (UL), we decoder utilize matrix (RM) theory obtain two accurate signal-to-interference plus noise ratio (SINR) approximations involving only large-scale fading...

Traditional approaches in the analysis of downlink systems decouple precoding and channel estimation problems. However, cellular with mobile users, these two problems are, fact, tightly coupled. In this paper, coupling is explicitly studied by accounting for training overhead error while determining overall system throughput. This paper studies problem utilizing imperfect estimates efficient linear user selection. It presents methods that take into account degree error. Information-theoretic...

A wireless massive MIMO system entails a large number (tens or hundreds) of base station antennas serving much smaller users, with gains in spectral-efficiency and energy-efficiency compared conventional technology. Until recently it was believed that multi-cellular system, even the asymptotic regime, as service tends to infinity, performance is limited by directed inter-cellular interference. This interference results from unavoidable re-use reverse-link training sequences (pilot...

We consider a single-cell downlink massive MIMO system in the presence of an adversary capable jamming and eavesdropping. show that, classical attacks eavesdropping data can be simultaneously rendered useless. Specifically, we secure degrees freedom (DoF) attained is as same maximum DoF under no attack. propose novel beamforming strategy that establishes information theoretic security without need to Wyner encoding. next introduce new attack involves pilot signals succession. such attack,...

Using algebraic geometry codes we give a polynomial construction of quantum with asymptotically nonzero rate and relative distance.Received 18 July 2000DOI:https://doi.org/10.1103/PhysRevA.63.032311©2001 American Physical Society