Low Latency Random Access for Small Cell Toward Future Cellular Networks

Sundo Kim,Junseok Kim,Sunghyun Choi,Seongwon Kim,Byonghyo Shim,Kitaek Lee

doi:10.1109/access.2019.2958991

Sundo Kim, Junseok Kim + Show 4 more

Open Access

https://doi.org/10.1109/access.2019.2958991

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Journal: IEEE Access	Publication Date: Jan 1, 2019
Citations: 10	License type: CC BY 4.0

Affiliation: Seoul National University, Samsung (South Korea)

Abstract

In future cellular networks, performance target includes not only increasing data rate, but also reducing latency. The current LTE-Advanced systems require four message exchanges in the random access and uplink transmission procedure, thus inducing high latency. In this paper, we propose a 2-way random access scheme which effectively reduces the latency. The proposed 2-way random access requires only two messages to complete the procedure at the cost of increased number of preambles. We study how to generate such preambles and how to utilize them. According to extensive simulation results, the proposed random access scheme significantly outperforms conventional schemes by reducing latency by up to 43%. We also demonstrate that computational complexity slightly increases in the proposed scheme, while network load is reduced more than a half compared to the conventional schemes.

Highlights

From 1G to 4G Long Term Evolution-Advanced (LTE-A), major goal of cellular systems was to achieve the throughput improvement over the previous generation
We note that the reduction of core latency is an important issue but we do not consider it in this work since the primary purpose of this work is to propose a new random access scheme reducing the control plane latency as well as the uplink transmission latency
For the 2-way random access, we propose a new preamble that conveys the special information, i.e., purpose of random access and buffer status of User Equipment (UE)

Summary

INTRODUCTION

From 1G to 4G Long Term Evolution-Advanced (LTE-A), major goal of cellular systems was to achieve the throughput improvement over the previous generation. The control plane latency, caused by the random access to set up an RRC connection, is the time required for User Equipment (UE) to transit state from RRC_IDLE to RRC_CONNECTED.. We note that the reduction of core latency (the latency between eNB and core network) is an important issue but we do not consider it in this work since the primary purpose of this work is to propose a new random access scheme reducing the control plane latency as well as the uplink transmission latency. Using NS-3 system-level simulations [14], we show that the proposed 2-way random access scheme achieves significant reduction (up to 43%) in the control plane latency and uplink transmission latency over the conventional random access.

RELATED WORK

PROPOSED RANDOM ACCESS

PREAMBLE SEQUENCE ANALYSIS

PERFORMANCE EVALUATION

Findings

CONCLUSION