System-level performance of LTE-Advanced with joint transmission and dynamic point selection schemes

Abstract

In this article, we present a practical coordinated multipoint (CoMP) system for LTE-Advanced. In this CoMP system, cooperation is enabled for cell-edge users via dynamic switching between the normal single-cell operation and CoMP. We first formulate a general CoMP system model of several CoMP schemes. We then investigate a practical finite-rate feedback design that simultaneously supports interference coordination, joint transmission (JT), and dynamic point selection (DPS) with a varying number of cooperating transmission points while operating a single-cell transmission as a fallback mode. We provide both link-level and system-level results for the evaluation of different feedback options for general CoMP operation. The results show that there are substantial performance gains in cell-edge throughputs for both JT and DPS CoMP over the baseline Release 10 LTE-Advanced with practical feedback options. We also show that CoMP can enable improved mobility management in real networks.

Centralized coordinated scheduling in LTE-Advanced networks

“…One major enhancement in LTE-Advanced, with respect to the LTE Release 8 CRSs, is the possibility to configure muted CSI-RSs, i.e., CSI-RSs with zero transmission power, enabling the UEs to estimate CSI from specific neighboring BSs without interference from the serving BS. Due to this feature, the UEs can generate multiple CSI R-11 lte reports that reflect different serving and interfering conditions in the network [20,21].…”

“…Additionally, the total instantaneous achievable data rate of UE n, on PRB l, denoted by r n,l , is calculated in (27d) as the achievable data rate for the selected interference scenario j, as defined by the coordinated decision variable s n,l,j . It is worth to notice that there is a one-to-one mapping between r n,l,j and s n,l,j , thus, there is no requirement for a lookup table function as used in (20). Furthermore, the constraints in (27e) are incorporated as a preprocessing step to ensure that no PRB is scheduled to UEs for which a maximum PF metric for the corresponding interference scenario j is not available.…”

“…Over the past years, important research has been carried out regarding CoMP schemes under different network architectures and CSI assumptions. In [20] and [21], JT and DPS schemes based on the enhanced CSI reports supported by Long Term Evolution (LTE)-Advanced Release 11, in the following denoted as CSI R-11 lte reports, have been investigated. The results therein show throughput gains for the cell-edge users mainly, and the possibility to improve mobility management by means of DPS.…”

Comp-Jt With Dynamic Cell Selection, Global Precoding Matrix And Irc Receiver For Lte-A

“…In order to maximize the sum-rate of UEs under JT mode, beam-forming matrix is calculated using maximum capacity criteria. In [12] a general formulation of CoMP JT and DPS is provided. Edge users can switch between the modes of CoMP or fall back to the single eNB based on channel condition.…”

“…eNBs communicate with one another through the backhaul network such as X2 interface via fiber optics. Figures 1, 2, and 3 show three different schemes for CoMP [12]. Among these three types of DL CoMP techniques this paper is interested in JT.…”