Results 31 to 40 of about 4,905,659 (296)

Latency and Reliability Analysis of Cellular Networks in Unlicensed Spectrum

IEEE Access, 2020
In this paper, the achievable latency-reliability performance of a standalone cellular network over the 5 GHz unlicensed spectrum is analysed. Fulfilling strict latency-reliability requirements comes with significant challenges for unlicensed operation ...
Roberto Maldonado, Claudio Rosa, Klaus I. Pedersen   +2 more
doaj   +1 more source

Grant-Free Massive NOMA: Outage Probability and Throughput

CoRR, 2017
In this paper, we consider a massive uncoordinated non-orthogonal multiple access (NOMA) scheme where devices have strict latency requirements and no retransmission opportunities are available. Each device chooses a pilot sequence from a predetermined set as its signature and transmits its selected pilot and data simultaneously. A collision occurs when
Rana Abbas, Mahyar Shirvanimoghaddam, Yonghui Li 0001, Branka Vucetic   +3 more
openaire   +2 more sources

Design Framework of Fourier-Based Non-Orthogonal Sequences for Sparse Activity Detection in Multicell Massive Connectivity

IEEE Access, 2022
In massive machine-type communications (mMTC), grant-free access is a key enabler for a massive number of users to be connected to a base station with low signaling overhead and low latency. In this paper, new Fourier-based sequence sets are proposed for
Nam Yul Yu
doaj   +1 more source

A Hybrid-Grant Random Access Scheme in Massive MIMO Systems for IoT

IEEE Access, 2020
The grant-free random access (RA) can minimize the access delay but also brings severe data transmission interferences. To overcome this defect, we propose a new RA scheme that inserts a base station (BS) broadcasting message after user equipments (UEs ...
Qi Zhang, Shi Jin, Hongbo Zhu
doaj   +1 more source

Joint Beamforming and Compressed Sensing for Uplink Grant-Free Access

IEEE Transactions on Wireless Communications, 2023
Compressed sensing (CS)-based techniques have been widely applied in the grant-free non-orthogonal multiple access (NOMA) to a single-antenna base station (BS). In this paper, we consider the multi-antenna reception at the BS for uplink grant-free access for the massive machine type communication (mMTC) with limited channel resources.
Guoqing Xia, Pei Xiao 0001, Bohan Li 0005, Yue Zhang 0011, Huiyu Zhou 0001   +4 more
openaire   +3 more sources

Manifold-Based Optimizations for RIS-Aided Massive MIMO Systems

IEEE Open Journal of the Communications Society
Manifold optimization (MO) is a powerful mathematical framework that can be applied to optimize functions over complex geometric structures, which is particularly useful in advanced wireless communication systems, such as reconfigurable intelligent ...
Wilson De Souza Junior, David William Marques Guerra, Jose Carlos Marinello Filho, Taufik Abrao, Ekram Hossain   +4 more
doaj   +1 more source

Outage Performance Analysis of RSMA-Aided Semi-Grant-Free Transmission Systems

IEEE Open Journal of the Communications Society, 2023
In this paper, we analyze the outage performance of a rate-splitting multiple access (RSMA)-aided semi-grant-free (SGF) transmission system, in which a grant-based user (GBU) and multiple grant-free users (GFUs) access the base station by sharing the ...
Fengcheng Xiao, Xingwang Li, Liang Yang, Hongwu Liu, Theodoros A. Tsiftsis   +4 more
doaj   +1 more source

Reed-Muller Sequences for 5G Grant-Free Massive Access [PDF]

GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
We propose to use second order Reed-Muller (RM) sequence for user identification in 5G grant-free access. The benefits of RM sequences mainly lie in two folds, (i) support of much larger user space, hence lower collision probability and (ii) lower detection complexity.
Huazi Zhang, Rong Li 0001, Jun Wang 0062, Yan Chen 0010, Zhaoyang Zhang 0001   +4 more
openaire   +2 more sources

Grant-Free Rateless SCMA for Cellular Internet of Things Networks

IEEE Access, 2019
For supporting the massive connectivities and better adapting the high dynamical channel states of the cellular Internet of things networks, in this paper we proposed a new grant-free rateless sparse code multiple access (RSCMA) protocol. In the proposed
Zhipeng Pan, Jing Lei, Wei Liu, Junshan Luo, Chaojing Tang   +4 more
doaj   +1 more source

Rethinking Grant-Free Protocol in mMTC

GLOBECOM 2024 - 2024 IEEE Global Communications Conference
This paper revisits the identity detection problem under the current grant-free protocol in massive machine-type communications (mMTC) by asking the following question: for stable identity detection performance, is it enough to permit active devices to transmit preambles without any handshaking with the base station (BS)?
Minhao Zhu, Yifei Sun, Lizhao You, Zhaorui Wang 0001, Ya-Feng Liu, Shuguang Cui   +5 more
openaire   +2 more sources