An evolution of HSPA has been specified based on the studies, which added multiple input/ multiple output (MIMO) antenna capability and 16QAM (Uplink)/ 64QAM (Downlink) modulation. The improvements in the radio access network for continuous packet connectivity will help the evolving architecture - HSPA+ - achieve uplink speeds of 11Mbps and Downlink speeds of 42Mbps. HSPA+, also known as Evolved High-Speed Packet Access is a wireless broadband standard defined in 3GPP release 7. The 3GPP roadmap from HSPA to HSPA+ and then to LTE has been well defined in standards development work with the final closing of Release 8.
HSPA+ is a simple upgrade to HSPA networks existing today. HSPA+ provides a performance advantage for the GSM-HSPA operators providing OFDMA equivalent performance in 5X5 MHz spectrum allocations
with only incremental investment.HSPA+ doubles the data capacity over HSPA and over WCDMA, it offers more than double voice capacity. Lower latency is being projected as one of the key advantages. Higher order modulation schemes are utilized to enhance the data rates. HSPA+ networks are likely to co-exist with LTE networks during the initial years, after which the oprerators may want to shift to the next level of efficiency. The discontinuous transmit/receive feature allows the device to gate off the control channels when there is no user data to send. Similarly the receiver is turned off at certain agreed intervals when there is no downlink information to the device. Such a synchronized operation allows the device to shut off its transmitter and receiver blocks completely, which significantly improves the device battery life for voice over HSPA services.
HSPA+ thus provides an excellent technology evolution path from HSPA, enabling operators to maximize their return on existing investments.