Dynamic TDD in LTE small cells

dc.contributorAalto Universityen
dc.contributor.authorKerttula, Jussi
dc.contributor.authorMarttinen, Aleksi
dc.contributor.authorRuttik, Kalle
dc.contributor.authorJäntti, Riku
dc.contributor.authorNazrul Alam, Mirza
dc.contributor.departmentDepartment of Communications and Networking
dc.description.abstractDynamic time-division duplexing (TDD) enables adjustments of uplink (UL) and downlink (DL) resources flexibly according to the instantaneous traffic load. Long-Term Evolution (LTE) systems can be implemented in TDD mode (TD-LTE). However, the dynamic change of a TDD configuration has not been well supported and investigated. In large macro cells, the high transmit power of base stations (BSs) easily blocks the weaker user equipment’s (UE) UL signal (called the UL-DL interference); and therefore, neighboring cells usually operate with the same TDD configuration. In small cells, such as femtocells, the BS and UE transmission powers are in the same order and the system can afford to have overlapping UL-DL subframes. In addition, when DL load is light, the BS transmits empty DL subframes with only a reference signal (RS). In this paper, we measured the interference caused by DL RS. This interference is not negligible; and therefore, it is beneficial to reduce the amount of DL subframes by switching lightly loadedBSs to UL-heavy subframe configuration. We illustrate with simulations that this can improve system efficiency. Changing the subframe configuration dynamically has a switching-related cost. Frequent switching between subframe configurations can actually decrease throughput. We describe conditions where configuration change is beneficial. We also propose an algorithm that decreases the switching overhead and improves the ability to adapt to varying loads.en
dc.description.versionPeer revieweden
dc.identifier.citationKerttula , J , Marttinen , A , Ruttik , K , Jäntti , R & Nazrul Alam , M 2016 , ' Dynamic TDD in LTE small cells ' , EURASIP Journal on Wireless Communications and Networking , vol. 2016 , 194 , pp. 1-10 . https://doi.org/10.1186/s13638-016-0696-zen
dc.identifier.otherPURE UUID: f20abec3-a937-4316-ab92-e2ee9e42a1ef
dc.identifier.otherPURE ITEMURL: https://research.aalto.fi/en/publications/f20abec3-a937-4316-ab92-e2ee9e42a1ef
dc.identifier.otherPURE FILEURL: https://research.aalto.fi/files/7093416/art_3A10.1186_2Fs13638_016_0696_z.pdf
dc.relation.ispartofseriesEURASIP Journal on Wireless Communications and Networkingen
dc.relation.ispartofseriesVolume 2016, issue 1en
dc.titleDynamic TDD in LTE small cellsen
dc.typeA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessäfi