Definition:
High Speed Downlink Packet Access was released in 3GPP-Third Generation Partnership Project Release 5 for indoor and urban outdoor high speed data access at 10 MBPS-Mega Bits Per Second range (14.4 MBPS theoretical). By using MIMO-Multiple Input Multiple Output (shown next) as well as other antenna systems and asymmetric allocation of frequency spectrum in multi-carrier cells higher data speeds are forecasted.