Paper Info
Title
Latency And Reliability Analysis Of Cellular Networks In Unlicensed Spectrum
Abstract
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, especially due to mandatory channel access procedures. Using MulteFire as the reference system-model, an analysis of a highly realistic multi-cell network with bi-directional traffic shows that latency of 23 ms with a reliability level of 99.99% is achievable for low-loads, while latency is increased to 79 ms at high-loads. Different techniques are described to improve the system performance. First, a pre-emptive scheme to cope with continuous uplink listen before talk (LBT) failures for uplink control transmissions is proposed. It provides a latency reduction of 24% at low-loads with two transmission opportunities and 11% for high-loads with three opportunities. Secondly, the possibility of skipping LBT performance under given conditions is evaluated. This results in a lower uplink LBT failure rate which translates to a latency reduction of 8% for low-loads and up to 14% for high-loads, at 99.99% reliability. Thirdly, as an alternative to grant-based uplink, grant-free uplink is evaluated. Grant-free uplink achieves better performance than grant-based uplink at low-loads, offering 50% lower uplink latency. At high-loads, the gain of grant-free uplink decreases due to the high number of simultaneous transmissions.
Year
DOI
Venue
2020
10.1109/ACCESS.2020.2978032
IEEE ACCESS
Keywords
DocType
Volume
Uplink, Reliability, 3GPP, Bandwidth, Cellular networks, 5G mobile communication, Downlink, Latency, reliability, unlicensed spectrum, MulteFire, listen before talk, radio resource management, system-level performance, scheduling, hybrid automatic repeat request
Journal
8
ISSN
Citations 
PageRank 
2169-3536
0
0.34
References 
Authors
0
3
Name
Order
Citations
PageRank
Roberto Maldonado Cuevas101.69
Claudio Rosa242347.25
Klaus I. Pedersen31732194.03