Recently, the 3GPP RAN WG1 (RAN1) started working on a Study Item that focuses on introducing 3D MIMO Channel Models for system-level performance evaluation of 3D MIMO and Full- Dimension (FD) MIMO features in LTE-A. In this Study Item, simulation scenarios and environments have been defined and agreed upon for the extension of the current 3GPP/ITU Channel Model. In this paper, we present some of the major modifications that have been brought in the 3GPP 3D MIMO Channel and antenna models. We also present the problem of computing the Reference Signal Received Power (RSRP) by accounting for the Small Scale Parameters (SSPs), which relates closely to the problem of determining the serving cell. We present two RSRP computation models that account for the effects of SSPs and evaluate their performance through system-level simulations. We observe that the behaviour of the 3D MIMO Channel Model is significantly impacted by how the RSRP is computed. We provide some preliminary results on the 3D MIMO channel and investigate the different parameters impacting the 3D MIMO channel's behaviour.

Three dimensional (3D) beamforming (also elevation beamforming) is now gaining interest among researchers in wireless communication. The reason can be attributed to its potential for enabling a variety of strategies such as sector or user specific elevation beamforming and cell-splitting. Since these techniques cannot be directly supported by current LTE releases, the 3GPP is now working on defining the required technical specifications. In particular, a large effort is currently being made to get accurate 3D channel models that support the elevation dimension. This step is necessary as it will evaluate the potential of 3D and full dimensional (FD) beamforming techniques to benefit from the richness of real channels. This work aims at presenting the on-going 3GPP study item “study on 3D-channel model for elevation beamforming and FD-MIMO studies for LTE” and positioning it with respect to previous standardization works.

This work concerns a limited feedback scheme taking into account the channel time-correlation during the feedback design in slow fading environment. We consider the Coordinated MultiPoint (COMP) system model with other-cell interference (OCI). We determine the feedback updating period which is triggered by the transmitters to enable the receiver to send the CSI. This updating period is function of the channel temporal correlation, available feedback bits, and the number of transmit antennas. An optimal updating period is derived such that it guarantees that the average signal-to-interference-and-noise ratio (SINR) is greater than or equal to that of the conventional feedback scheme that does not adapt its feedback period to the temporal correlation. The numerical results show performance improvement in terms of overall capacity and feedback overhead reduction when comparing the proposed adaptive scheme with conventional feedback approaches.