TY - GEN
T1 - Enabling Grant-Free Access with Non-orthogonal Preambles and Multi-codebook SCMA
AU - Abebe, Ameha T.
AU - Kang, Chung G.
N1 - Funding Information:
————————————————————————————– This work was supported in part by Samsung Research in Samsung Electronics.
Publisher Copyright:
© 2019 IEEE.
PY - 2019/10
Y1 - 2019/10
N2 - Grant-free random access is one of the key elements in the emerging mobile system in which a low-latency communication requirement must be met to support a massive number of machine-type communication (mMTC) devices. The random access success rate of sparse code multiple access (SCMA)-based grant-free (GF) access is mainly determined by factors such as collision in random access resource selection, users' activity, and data misdetection. At the same time, it is challenging to decrease the effect of these factors while reducing signaling overhead. One approach to handle the challenge is to employ a large set of non-orthogonal preambles for active user detection and channel estimation while allowing users' data to be differentiated by their channel even if the same SCMA codebook (CB) is selected. In this paper, we introduce a new approach that maps a user's consecutive symbols to code words from different SCMA CBs in around-robin manner, as opposed to conventional SCMA in which a single codebook (CB) is employed per a user's random access transmission. It is also shown that the proposed multi-codebook SCMA-based GF access scheme outperforms the conventional single-codebook SCMA-based one by overloading of more users(up to 200%) while keeping the same preamble length, i.e., the same level of overhead.
AB - Grant-free random access is one of the key elements in the emerging mobile system in which a low-latency communication requirement must be met to support a massive number of machine-type communication (mMTC) devices. The random access success rate of sparse code multiple access (SCMA)-based grant-free (GF) access is mainly determined by factors such as collision in random access resource selection, users' activity, and data misdetection. At the same time, it is challenging to decrease the effect of these factors while reducing signaling overhead. One approach to handle the challenge is to employ a large set of non-orthogonal preambles for active user detection and channel estimation while allowing users' data to be differentiated by their channel even if the same SCMA codebook (CB) is selected. In this paper, we introduce a new approach that maps a user's consecutive symbols to code words from different SCMA CBs in around-robin manner, as opposed to conventional SCMA in which a single codebook (CB) is employed per a user's random access transmission. It is also shown that the proposed multi-codebook SCMA-based GF access scheme outperforms the conventional single-codebook SCMA-based one by overloading of more users(up to 200%) while keeping the same preamble length, i.e., the same level of overhead.
KW - Grant-free access
KW - Non-orthogonal preambles
KW - SCMA
KW - Zadoff-chu sequence
UR - http://www.scopus.com/inward/record.url?scp=85078238180&partnerID=8YFLogxK
U2 - 10.1109/ICTC46691.2019.8939908
DO - 10.1109/ICTC46691.2019.8939908
M3 - Conference contribution
AN - SCOPUS:85078238180
T3 - ICTC 2019 - 10th International Conference on ICT Convergence: ICT Convergence Leading the Autonomous Future
SP - 883
EP - 888
BT - ICTC 2019 - 10th International Conference on ICT Convergence
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 10th International Conference on Information and Communication Technology Convergence, ICTC 2019
Y2 - 16 October 2019 through 18 October 2019
ER -