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Mobile Information Systems
Volume 2017 (2017), Article ID 7954631, 7 pages
https://doi.org/10.1155/2017/7954631
Research Article

Frame-Based Random Access with Interference Cancellation across Frames for Massive Machine Type Communications

Department of Information and Communication Engineering, Dongguk University, 30 Pildong-ro 1 Gil, Jung-gu, Seoul 100-715, Republic of Korea

Correspondence should be addressed to Minjoong Rim

Received 7 February 2017; Revised 25 April 2017; Accepted 15 June 2017; Published 19 July 2017

Academic Editor: Alessandro Bazzi

Copyright © 2017 Minjoong Rim and Seungyeob Chae. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

One of the main requirements for next generation mobile or wireless communication systems is to effectively support a large number of machine type communication devices for Internet of things applications. In order to improve the random access capability in frame-based slotted Aloha environments, coded random access techniques have been proposed, in which multiple copies of a packet are transmitted per frame and the copies are cancelled out from the received signal if any single copy is successfully received. They, however, may increase the transmission power by sending multiple copies per frame. Above all, for systems with a small number of slots per frame, they may not be able to improve the performance by readily reaching a congested state. This paper proposes a new frame-based random access scheme, which sends at most one copy of a packet per frame but uses interference cancellation to improve the performance. If a successfully received packet is a retransmitted one, the previously transmitted signals for the packet can be cancelled out from the received signals for trying to decode other received packets. The proposed scheme has different characteristics than coded random access schemes and can be also combined with them to further improve the performance.