314 research outputs found
Multi-User Preemptive Scheduling for Critical Low Latency Communications in 5G Networks
5G new radio is envisioned to support three major service classes: enhanced
mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and
massive machine type communications. Emerging URLLC services require up to one
millisecond of communication latency with 99.999% success probability. Though,
there is a fundamental trade-off between system spectral efficiency (SE) and
achievable latency. This calls for novel scheduling protocols which
cross-optimize system performance on user-centric; instead of network-centric
basis. In this paper, we develop a joint multi-user preemptive scheduling
strategy to simultaneously cross-optimize system SE and URLLC latency. At each
scheduling opportunity, available URLLC traffic is always given higher
priority. When sporadic URLLC traffic appears during a transmission time
interval (TTI), proposed scheduler seeks for fitting the URLLC-eMBB traffic in
a multi-user transmission. If the available spatial degrees of freedom are
limited within a TTI, the URLLC traffic instantly overwrites part of the
ongoing eMBB transmissions to satisfy the URLLC latency requirements, at the
expense of minimal eMBB throughput loss. Extensive dynamic system level
simulations show that proposed scheduler provides significant performance gain
in terms of eMBB SE and URLLC latency
Quasi-Dynamic Frame Coordination For Ultra- Reliability and Low-Latency in 5G TDD Systems
The fifth generation (5G) mobile technology features the ultra-reliable and
low-latency communications (URLLC) as a major service class. URLLC applications
demand a tight radio latency with extreme link reliability. In 5G dynamic time
division duplexing (TDD) systems, URLLC requirements become further challenging
to achieve due to the severe and fast-varying cross link interference (CLI) and
the switching time of the radio frame configurations (RFCs). In this work, we
propose a quasi-dynamic inter-cell frame coordination algorithm using hybrid
frame design and a cyclic-offset-based RFC code-book. The proposed solution
adaptively updates the RFCs in time such that both the average CLI and the
user-centric radio latency are minimized. Compared to state-of-the-art dynamic
TDD studies, the proposed scheme shows a significant improvement in the URLLC
outage latency, i.e., 92% reduction gain, while boosting the cell-edge capacity
by 189% and with a greatly reduced coordination overhead space, limited to
B-bit
Opportunistic Spatial Preemptive Scheduling for URLLC and eMBB Coexistence in Multi-User 5G Networks
A Survey of Scheduling in 5G URLLC and Outlook for Emerging 6G Systems
Future wireless communication is expected to be a paradigm shift from three basic service requirements of 5th Generation (5G) including enhanced Mobile Broadband (eMBB), Ultra Reliable and Low Latency communication (URLLC) and the massive Machine Type Communication (mMTC). Integration of the three heterogeneous services into a single system is a challenging task. The integration includes several design issues including scheduling network resources with various services. Specially, scheduling the URLLC packets with eMBB and mMTC packets need more attention as it is a promising service of 5G and beyond systems. It needs to meet stringent Quality of Service (QoS) requirements and is used in time-critical applications. Thus through understanding of packet scheduling issues in existing system and potential future challenges is necessary. This paper surveys the potential works that addresses the packet scheduling algorithms for 5G and beyond systems in recent years. It provides state of the art review covering three main perspectives such as decentralised, centralised and joint scheduling techniques. The conventional decentralised algorithms are discussed first followed by the centralised algorithms with specific focus on single and multi-connected network perspective. Joint scheduling algorithms are also discussed in details. In order to provide an in-depth understanding of the key scheduling approaches, the performances of some prominent scheduling algorithms are evaluated and analysed. This paper also provides an insight into the potential challenges and future research directions from the scheduling perspective
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