esource blocks) such that inter-cell interference is kept under control. ICIC is inherently a multi-cell RRM function that needs to take into account information (e.g., the resource usage status and traffic load situation) from multiple cells. The preferred ICIC method may be different in the uplink and downlink [14]. 3.9.3 Multi-Antennas Transmission 3GPP specifications recommends that all the LTE terminals have at least two receive antennas. This helps the networks to be planned, assuming at least the presence of downlink diversity (mobile receive diversity). LTE also supports transmit diversity, spatial multiplexing techniques like SU-MIMO (Single- user Multiple Input Multiple Output) and MU-MIMO (Multi-user MIMO) with up to four antennas, and beamforming. These schemes are shown in Figure 3.30 [24]. Spatial division multiplexing (SDM) of multiple modulation symbol streams to a single UE using the same time-frequency (-code) resource, also referred to as Single-User MIMO (SU-MIMO) is supported. When a MIMO channel is solely assigned to a single UE, it is known as SU-MIMO. Spatial division multiplexing of modulation symbol streams to different UEs using the same time-frequency resource, also referred to as MU-MIMO, is also supported. There is semi-static switching between SU-MIMO and MU-MIMO per UE. MIMO involves the use of multiple transmit antennas at the base station and multiple receive antennas at the terminals. Receiver algorithms such as dirty paper coding19 can also be employed in combination 19 Dirty paper coding (DPC) is a technique for efficient transmission of digital data through a channel that is subject to some interference that is known to the transmitter. The technique consists of precoding the data SO as to cancel the effect of the interference. Next Generation Mobile Communications Ecosystem Diversity for improved Beam-forming for improved coverage system performance (less cells to cover a given area) Spatial-division multiple access Multi-layer transmission ("MU-MIMO") for improved capacity 