Dynamic TDD Interference Mitigation by Using Soft Reconfiguration
Date Issued
2014
Date
2014
Author(s)
Lin, Yi-Ting
Abstract
In the LTE networks, there is a need to develop flexible schemes to adjust the UL and DL configuration of the UEs in order to meet the increasing demand for data due to the increasing use of multimedia. LTE Dynamic Time- Division duplexing (TDD) was created for this reason; it can ensure the base station selects a proper UL and DL pattern for different traffic demands in order to maximize the throughput of the small cell networks. However, Dynamic TDD’s advantage is limited in high density deployment scenarios due to the fact that the interference due to the number of base stations is very high.In the 3GPP specification, there are 7 different LTE TDD configurations; each configuration has a distinct UL / DL pattern. Each base station must select a configuration to use. Our research focuses on the case where the base station’s, femto cell’s, or other UE’s signal strength is different from that of other UEs. In this scenario, the signal strength from the UE is insufficient and the interference will cause the SINR to decrease. In the scenario of a UE being UL and another UE being DL, the SINR and throughput will be lower than the scenario where both are UL. There are two kinds of scheme for the base station. In the first scenario, traffic adaptation, each base station will choose the appropriate configuration for the traffic demand. In the second scenario,some base stations experiencing a high interference will cluster together, i.e. they will use the same configuration in order to mitigate the interference in UL-DL case; as a result, the SINR and throughput will increase in UL case. There is still a problem in the diverse traffic scenario as the configuration of the cluster is unable to match the traffic pattern of every base station in cluster. In this research, we discuss this scenario and balance the advantages of traffic adaptation with clustering. There are three parts to the algorithm. In the first part, the UEs will group as in the clustering and obtain the reconfiguration group tag, which will be used in reconfiguration. In the second part, if some base stations experience high interference, a high interference alert is raised and the group will reconfigured based on the reconfiguration group tag and the concession map, which helps mitigate the interference for DL. In the third part, each base station in algorithm will revert back to traffic adaptation when the high interference alert lifted.
Subjects
TDD
LTE
Interference Mitigation
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-R01942129-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):dd4da694f33fbcbfb1fab17fff466af5