MIMO: Channel Capacity

Compared to a conventional single antenna system, the channel capacity of a multiple antenna system with NT transmit and NR receive antennas can be increased by the factor of min (NT , NR), without using additional transmit power or spectral bandwidth. Multiple antenna techniques can be broadly classified into two categories: diversity techniques and spatial-multiplexing techniques. When the spatial-multiplexing techniques are used, the maximum achievable transmission speed can be the same as the capacity of the MIMO channel; however, when the diversity techniques are used, the achievable transmission speed can be much lower than the capacity of the MIMO channel. This chapter discusses the capacity of the MIMO wireless channel. It addresses useful matrix identities that are frequently used in the expression of the corresponding capacity. The chapter also derives the MIMO system capacities for deterministic and random channels. Controlled Vocabulary Terms channel capacity; MIMO systems