David Mazzarese

Coordinated multipoint transmission and reception in LTE-advanced: deployment scenarios and operational challenges

3GPP has completed a study on coordinated multipoint transmission and reception techniques to facilitate cooperative communications across multiple transmission and reception points (e.g., cells) for the LTE-Advanced system. In CoMP operation, multiple points coordinate with each other in such a way that the transmission signals from/to other points do not incur serious interference or even can be exploited as a meaningful signal. The goal of the study is to evaluate the potential performance benefits of CoMP techniques and the implementation aspects including the complexity of the standards support for CoMP. This article discusses some of the deployment scenarios in which CoMP techniques will likely be most beneficial and provides an overview of CoMP schemes that might be supported in LTE-Advanced given the modern silicon/DSP technologies and backhaul designs available today. In addition, practical implementation and operational challenges are discussed. We also assess the performance benefits of CoMP in these deployment scenarios with traffic varying from low to high load.

Coordinated multipoint transmission and reception in LTE-advanced systems

Advanced interference mitigation techniques relying on multipoint coordination have attracted significant attention from the wireless industry and academia in the past few years. In 3GPP LTE-Advanced, a work item on Coordinated Multiple Point transmission and reception (CoMP) was initiated in September 2011, and it is one of the core features of Release 11. The objective of this work item is to provide the necessary specification support to efficiently realize the benefits of cooperative transmission in the downlink and cooperative reception in the uplink. This article discusses the specification support for CoMP and the motivations behind the specific design choices. The deployment scenarios that were considered for the application of CoMP in Release 11 are also presented.

An efficient feedback and scheduling scheme for cooperative multiple-point transmission in heterogeneous networks

Cellular networks are evolving towards a mixture of macro cells and small cells, thereby increasing the number of cell sites to serve traffic hotspots. This trend poses challenges for managing inter-cell interference and traffic offloading, since a multitude of transmitters of different power classes creates imbalance between the downlink and uplink coverage. Conventional network planning and interference randomization techniques offer limited protection in such environments. Recently standardized semi-static inter-cell coordination strategies provide some capability for interference avoidance. This paper presents a scheme for dynamic coordination of the interference using cooperative multi-point transmission techniques in heterogeneous networks. The scheme relies on an efficient feedback technique coupled with a scheduling algorithm which dynamically handles inter-cell interference and traffic offloading between cell layers.