Performance Evaluation and Analysis on Group Mobility of Mobile Relay for LTE Advanced System

Abstract

High Speed Railway(HSR) scenario was currently agreed as the main scenario in the 3GPP Rel.11 study item, Mobile Relay for E-UTRA. Usually, communications of high-speed railway systems suffer from problems such as Doppler spread, radio condition abrupt change and handover failure. Mobile relay is a promising scheme to solve these problems, but the quantitative performance improvement to HSR has not been fully evaluated and analyzed. In this paper, a high speed scenario with mobile relay integrated is presented to analyze these issues for LTE Advanced system. The proposed mobile relay solution with group mobility is evaluated by a series of system simulation which witnesses an improvement in train user throughput as well as system throughput, and higher handover success ratio with a decrease in radio link failure ratio.

Transmit Power Minimization and Base Station Planning for High-Speed Trains with Multiple Moving Relays in OFDMA Systems

“…is the vector that contains the Lagrange multipliers associated to constraints (11) and (12). The dual function g(λ) is given as follows…”

“…whereP t is the peak power at the transmitter t. Constraint (12) ensures that the QoS of the receiver r is satisfied, while constraint (13) indicates that each subcarrier can be allocated to only one UE and, at maximum, one UE can be served by K subcarriers. Note that constraint (12) is written as R Um (P Ri ) ≥ R Um th , ∀m = 1, · · · , M i , for the access link inside wagon i, and as R Ri (P B ) ≥ R Ri th , ∀i = 1, · · · , L, for the backhaul link between the BS and MRs.…”

“…VPL can be negligible by introducing two antennas connected together by a cable; outside and inside the vehicle. The outside antenna communicates with the BS, while the inside antenna communicates with the UEs inside the vehicle [12]- [14].…”

LTE-Advanced Radio Access Enhancements: A Survey

“…Relay nodes can be used in situations where providing backhaul is impractical or expensive. Installing RNs on mobile vehicles such as buses or in High Speed Railways (HSR) is another interesting application of the relays which is under consideration by 3GPP and ITU [154,155]. RN can also be considered as a special case of the small cell deployment and RNs can be compared with Pico and Femto cells in terms of performance, cost and energy efficiency [156][157][158].…”

Moving cells: a promising solution to boost performance for vehicular users

“…First, group handover (HO) can be performed by regarding the UE served by the same MRN as a group. Depending on the mobility management schemes, the signaling at the radio network side and probability of HO failure of the vehicular UE could be noticeably lowered [4,9]. Second, since MRNs are not as limited by size and power as regular UE, they can better exploit various smart antenna techniques and advanced signal processing schemes.…”