In this paper, we consider a new interference problem caused by idle small cells, which have no associated user equipment in ultra-dense small cell long-term evolution (LTE) networks. Specifically, we investigate the effect of idle small cells on the signal to interference and noise ratio (SINR) of the cell-specific reference signal (CRS) and the data signals. We confirm that CRS interference from idle small cells produces uneven interference pattern across CRS and data signals and eventually causes an SINR mismatch between CRS and data signals as well as between data signals with and without CRS symbols. In addition, these phenomena become severe with cell densification. In order to solve this mismatch problem, we propose a simple link adaptation framework, which utilizes clustered CRS assignment and hybrid SINR measurement. The numerical results show that the proposed method improves the average sum throughput compared with the conventional approaches. Overall, this paper sheds new light on investigating and coping with the interference problem coming from idle small cells in future ultra-dense small cell LTE networks.
Bibliographical noteFunding Information:
Manuscript received January 26, 2017; revised June 8, 2017 and October 4, 2017; accepted November 14, 2017. Date of publication December 15, 2017; date of current version February 9, 2018. This work was supported in part by the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2015R1A2A1A01006162) and in part by Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government (MSIP) (2016-0-00181-002, Development on the core technologies of transmission, modulation and coding with low-power and low-complexity for massive connectivity in the IoT environment). The associate editor coordinating the review of this paper and approving it for publication was R. Brown. (Corresponding author: Daesik Hong.) Y. Park, J. Heo, S. Weon, S. Choi, and D. Hong are with the School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, South Korea (e-mail: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org).
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics