I am often asked for facts and figures on current wireless technologies such as Evolved High Speed Packet Access (HSPA+), Long Term Evolution (LTE) and LTE-Advanced, so I thought it would be worth capturing some of these in this blog post. There have been dramatic advances in both HSPA+ and LTE since their first arrival in 3GPP Releases 7 and 8, respectively. It is widely known that since the advent of LTE-Advanced in 3GPP Release 10, the LTE family of standards now fulfils the criteria of a true 4G mobile system, as laid down by the ITU. However, what is not so commonly known is that, as of 3GPP Release 11, HSDPA+ also satisfies many of these requirements, including peak spectral efficiency, spectrum flexibility and latency. While LTE deployment is progressing at a pace, HSPA+ will remain the dominant platform for mobile broadband services for some time to come, and upgrades to HSPA+ networks will be an important element in meeting the demand for mobile data.
Given the complexity of HSPA+ and LTE, and the many different ways in which they can be deployed and configured, it is impossible to reflect all of their ins and outs in one short blog post. In the following table I have captured major features of their designs along with headline performance figures, as of 3GPP Release 11 (frozen September 2012). As we have pointed out many times before, while the peak performance of these technologies is one measure of their capabilities, it should not be taken to reflect typical performance in a real wide-area network. For example, peak throughput figures will be attainable only when the ultimate configuration is deployed (e.g. using the maximum bandwidth and the highest order MIMO configuration) and when the mobile terminal is operating in ideal radio conditions (e.g. strong radio signalling and low loading of the cell). Typical performance in a real network may be significantly lower than the peak figures, but nonetheless these are highly impressive numbers, and it is worth pointing out that both HSPA+ and LTE systems include features to improve their performance in less than ideal conditions, such as near the edge of a cell.
Elsewhere in the Wireless Blog you will find articles on some of the features mentioned here, including LTE carrier aggregation, enhanced small cells for LTE and the evolution of 3GPP standards for LTE.
|Evolved High Speed Packet Access (HSPA+)||Long Term Evolution (LTE) and LTE Advanced|
|First 3GPP Release||Release 7 (frozen 2007)||LTE: Release 8 (frozen 2008)
LTE Advanced: Release 10 (frozen 2011)
|Multiple access method||Code Division Multiple Access (CDMA)||Downlink: Orthogonal Frequency Domain Multiple Access (OFDMA)
Uplink: Single Carrier Frequency Domain Multiple Access (SC-FDMA)
|Duplex method||Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD)||FDD or TDD|
|Modulation||Up to 64 level Quadrature Amplitude Modulation (QAM)||Up to 128 level QAM
|Carrier bandwidth||5MHz||1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz or 20MHz|
|Carrier aggregation||Multi-Carrier High Speed Downlink Packet Access (MC-HSDPA) allows aggregation of up to eight 5MHz downlink carriers.|
Dual-Carrier High Speed Uplink Packet Access (DC-HSUPA) allows aggregation of up to two 5MHz uplink carriers.
|Carrier aggregation enables the combination of up to five individual carriers to achieve a maximum bandwidth of 100MHz in the uplink or downlink.|
|Antennas||Downlink Multiple Input Multiple Output (MIMO) support for up to 4 transmit and 4 receive antennas.|
Uplink MIMO support for up to 2 transmit and 2 receive antennas.
|Downlink MIMO support for up to 8 transmit and 8 receive antennas.
Uplink MIMO support for up to 4 transmit and 4 receive antennas.
|Other features||Multiflow enables a mobile device to receive data from multiple cells, to improve downlink data rates near the edge of cells.|
Uplink beamforming improves data rates on the uplink.
|Co-ordinated multipoint (CoMP) transmission and reception enables simultaneous communication with multiple cells, to improve performance near the edge of cells.
Enhanced inter-cell interference coordination (eICIC) improves performance towards the edge of cells.
Relay nodes support network architectures comprising a variety of cell sizes.
|Peak throughput||Downlink: up to 336Mbps (64QAM, eight-carrier HSDPA, 2x2 MIMO or 64QAM, four-carrier HSDPA, 4x4 MIMO)|
Uplink: up to 69Mbps (64QAM, two-carrier HSUPA, 2x2 MIMO)
|Downlink: up to 3Gbps in low mobility situations (128QAM, 100MHz, 8x8 MIMO)
Uplink: up to 1.5Gbps in low mobility situations (128QAM, 100MHz, 4x4 MIMO)
|Peak spectral efficiency||Downlink: 16.8bps/Hz (64QAM, 4x4 MIMO).|
Uplink: 6.9bps/Hz (64QAM, 2x2 MIMO)
|Dowlink: 30bps/Hz (128QAM, 8x8 MIMO).
Uplink: 15bps/Hz (128QAM, 4x4 MIMO)
|Latency||Down to less than 10ms||Down to less than 10ms|
|Commercial deployments||315 commercial HSPA+ networks in 137 countries by May 2013 (source GSA)||175 networks in 70 countries by May 2013 (source GSA)|