Physical Cell ID Allocation in Multi-layer, Multi-vendor LTE networks

The evolution of radio access technologies and the user demand for increased capacity drives network deployments towards multiple cell layouts, often referred to as Heterogeneous Networks. With the ongoing rollout of commercial Long Term Evolution (LTE) networks, not only different radio access technologies are offered but LTE networks can also be multi-layered by themselves, consisting of differently sized cells providing coverage in overlapping areas. This comes with increased complexity of network management, which is even more relevant in common multi-vendor deployments, where coordinated configuration and operation of network elements provided by different vendors is essential. In this paper, we investigate and evaluate possible allocation schemes of an LTE radio parameter, the Physical Cell Identity. Results indicate that a particular allocation strategy, the range separation provides an elegant and efficient solution, which makes PCI management in multilayer, multi-vendor networks easier. The standardization relevance of the range separation scheme is also discussed.