A Grant-Based Random Access Protocol in Extra-Large Massive MIMO System

Nishimura, Otavio Seidi; Marinello, José Carlos; Abrão, Taufik

doi:10.1109/lcomm.2020.3012586

Cited by 29 publications

(33 citation statements)

References 6 publications

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“…Since the distances of the users to the antennas is of the same order of the array length L the average received power varies along the XL-MIMO array, and therefore we cannot consider a single long-term fading coefficient for a given user [3], [8]. Instead, we consider a long-term fading coefficient β m,k regarding the m-th antenna of the XL-MIMO array and the k-th user, similarly as in [3], [9], [10], [15], given by…”

Section: System Modelmentioning

confidence: 99%

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Antenna Selection for Improving Energy Efficiency in XL-MIMO Systems

Marinello

Abrão

Amiri

et al. 2020

IEEE Trans. Veh. Technol.

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We consider the recently proposed extra-large scale massive multiple-input multiple-output (XL-MIMO) systems, with some hundreds of antennas serving a smaller number of users. Since the array length is of the same order as the distance to the users, the long-term fading coefficients of a given user vary with the different antennas at the base station (BS). Thus, the signal transmitted by some antennas might reach the user with much more power than that transmitted by some others. From a green perspective, it is not effective to simultaneously activate hundreds or even thousands of antennas, since the power-hungry radio frequency (RF) chains of the active antennas increase significantly the total energy consumption. Besides, a larger number of selected antennas increases the power required by linear processing, such as precoding matrix computation, and short-term channel estimation. In this paper, we propose four antenna selection (AS) approaches to be deployed in XL-MIMO systems aiming at maximizing the total energy efficiency (EE). Besides, employing some simplifying assumptions, we derive a closed-form analytical expression for the EE of the XL-MIMO system, and propose a straightforward iterative method to determine the optimal number of selected antennas able to maximize it. The proposed AS schemes are based solely on longterm fading parameters, thus, the selected antennas set remains valid for a relatively large time/frequency intervals. Comparing the results, we find that the genetic-algorithm based AS scheme usually achieves the best EE performance, although our proposed highest normalized received power AS scheme also achieves very promising EE performance in a simple and straightforward way.

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Section: System Modelmentioning

confidence: 99%

“…A novel random access (RA) protocol for crowded XL-MIMO systems is proposed in [15]. Authors have proposed a decentralized and uncoordinated decision rule, which can be evaluated at the users side, for retransmitting or not the RA pilots during the connection stage, taking advantage of the XL-MIMO propagation features.…”

mentioning

confidence: 99%

Antenna Selection for Improving Energy Efficiency in XL-MIMO Systems

Marinello

Abrão

Amiri

et al. 2020

IEEE Trans. Veh. Technol.

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“…By solving Equation (10), we can obtain the effective timing offsets of the remaining (N i a − d i ) UEs. Thus, the estimated effective timing offsets are {𝜖 I 1 i , … , 𝜖 I s i , … , 𝜖…”

Section: The Proposed Random Access Schemementioning

confidence: 99%

“…However, the number of successful accessing UEs decreases with the increase of the number of contenders [9]. Recently, SUCRe also achieved performance gain for the extra‐large massive MIMO systems [10]. To ensure the fairness between UEs of the SUCRe scheme, an access class barring with power control (ACBPC) scheme was proposed in [11].…”

Section: Introductionmentioning

confidence: 99%

A novel random access scheme for M2M communication in crowded asynchronous massive MIMO systems

et al. 2021

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A new random access scheme is proposed to solve the intra-cell pilot collision for M2M communication in crowded asynchronous massive multiple-input multiple-output systems. The proposed scheme utilizes the proposed estimation method of signal parameters to estimate the effective timing offsets, and then active user equipments obtain their timing errors from the effective timing offsets for uplink message transmission. The mean squared error of the estimated effective timing offsets of user equipments and the uplink throughput are analysed. Simulation results show that, compared to the exiting random access scheme for the crowded asynchronous massive multiple-input multiple-output systems, the proposed scheme can improve the uplink throughput and estimate the effective timing offsets accurately at the same time.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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“…In [8], the authors introduce the concept of extra-large-scale MIMO or XL-MIMO by arguing that cellular mMIMO operates differently when the size of the antenna arrays is very large. Remarkably, the authors of [80] adapted the SUCRe protocol for XL-MIMO systems. Another promising approach is to completely get rid of the cellular perspective of design, giving rise to the notion of cell-free mMIMO networks [9].…”

Section: E1 Introductionmentioning

confidence: 99%

Efficient receivers for cellular massive mimo systems and random access in cell-free networks.

Rodrigues¹

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Esta dissertação aborda dois problemas de interesse para viabilizar as futuras redes sem fio de quinta e sexta geração (5G e 6G, respectivamente): o projeto de receptores eficientes e o acesso aleatório massivo. O primeiro problemaé discutido no contexto de redes celulares em que um número massivo de antenas, centenas a milhares, na estação rádio-base (BS) serve um grande número de usuários, dezenas a centenas, constituindo um sistema de múltiplasentradas e múltiplas-saídas massivo (M-MIMO). Para tornar esses sistemas mais escaláveis, adotamos o projeto de receptores iterativos baseados no algoritmo de Kaczmarz. Estudamos técnicas de aceleração para aumentar a eficiência de tais receptores, bem como sua robustez aos diferentes efeitos do canal sem fio. Além de efeitos clássicos de atenuação de potência e da correlação espacial, os efeitos do canal considerados abrangem o regime de sistemas MIMO de escala extra-grande (XL-MIMO), com o surgimento das chamadas não-estacionaridades espaciais. Os projetos de receptores consideram tanto arquiteturas de hardware de banda base centralizadas quanto arquiteturas descentralizadas. Os resultados mostram que nossos projetos de receptores baseados em métodos iterativos acelerados permitem um melhor controle do compromisso desempenho-complexidade sob diferentes condições do canal sem-fio. O segundo problema está relacionado ao estudo de como o acesso aleatório massivo pode ser resolvido em sistemas M-MIMO livres de células. Adaptamos ao sistema M-MIMO livre-de-células o protocolo denominado resolução de colisões baseado no usuário mais forte (SUCRe), proposto inicialmente para sistemas M-MIMO celulares. Este estudo permite-nos compreender melhor como o fato das antenas estarem distribuídas geograficamente pode ajudar a suportar um maior número de acessos simultâneos em futuras redes sem fios conceitualmente centradas no usuário móvel.

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A Grant-Based Random Access Protocol in Extra-Large Massive MIMO System

Cited by 29 publications

References 6 publications

Antenna Selection for Improving Energy Efficiency in XL-MIMO Systems

Antenna Selection for Improving Energy Efficiency in XL-MIMO Systems

A novel random access scheme for M2M communication in crowded asynchronous massive MIMO systems

Efficient receivers for cellular massive mimo systems and random access in cell-free networks.

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