Broadband Radio Interfaces Design for " 4G and Beyond" Cellular Systems in smart urban Environments

Broadband, ubiquitous and energy-efficient wireless networking is one of the pillars in the definition of a really smart urban environment. The latest developments in such a field concern with the forthcoming LTE-A standard, which will also involve small cell deployment for broadband coverage yielding increased quality of experience and reduced power consumption. Some open issues related to small cell LTE-A networking for smart city applications are discussed, together with feasible solutions that are investigated in terms of robust PHY-layer configurations, and fully-wireless backhaul (point-to-point transmission, point-to-multipoint etc.). One such issue is related to power-constrained uplink transmission, where cooperative multipoint (CoMP) in small cell network is considered assuring better quality of service and energy efficiency for user terminal. Moreover, a novel MIMO detection is conceived for LTE-A application based on MCBEP criterion that is suited for size-constrained small base station and guaranteeing near-optimum performance. A door open to upcoming mobile standards by proposing constant envelope techniques in the uplink providing flexible tradeoff between spectral and power efficiency for 5th generation applications. A complete wireless backhaul based on millimeter wave (mmWave), for network of small cells, is considered due to its cost effectiveness and flexible operations. A robust PHY-layer waveform based on space-time MIMO techniques have proven to be the right choice for non-line of sight operations whereas TH-IR UWB techniques are providing significant data rates in line-of-sight case. SDR-Implementation of advanced wireless strategies is important in order to realize network reconfigurability in future cellular networks where network functionalities can be changed on the fly .