Forget GPRS. We’ll kick this discussion fast and furious:
- the UMTS system, first offered in 2001, standardized by 3GPP, used primarily in Europe, Japan, China (however with a different radio interface) and other regions predominated by GSM 2G system infrastructure. The cell phones are typically UMTS and GSM hybrids. Several radio interfaces are offered, sharing the same infrastructure:
- The original and most widespread radio interface is called WCDMA. WCDMA networks can be upgraded to HSPA.
- The TD-SCDMA radio interface, was commercialised in 2009 and is only offered in China.
- The latest UMTS release, HSPA+, can provide peak data rates up to 56 Mbit/s in the downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the uplink.
- the CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in North America and South Korea, sharing infrastructure with the IS-95 2G standard. The cell phones are typically CDMA2000 and IS-95 hybrids. The latest release EVDO Rev B offers peak rates of 14.7 Mbit/s downstreams.
Pre-4G (or 3.5G if you will)
Both UMTS and CDMA2000 are evolving to LTE while WiMAX is different altogether.
- All-IP communications.
- Peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the ITU requirements.
- Scalable channel bandwidth, between 5 and 20 MHz, optionally up to 40 MHz.
- Peak link spectral efficiency of 15 bit/s/Hz in the downlink, and 6.75 bit/s/Hz in the uplink (meaning that 1 Gbit/s in the downlink should be possible over less than 67 MHz bandwidth)
- System spectral efficiency of up to 3 bit/s/Hz/cell in the downlink and 2.25 bit/s/Hz/cell for indoor usage
As far as ITU is concerned,
…of six technologies nominated for IMT-Advanced (the formal name for 4G) certification, just two have emerged victorious: 802.16m WiMAX 2 by IEEE — also known as WirelessMAN-Advanced — and LTE-Advanced by 3GPP.
Other technologies being developed to meet the 4G standard include Flash-OFDM and iBurst/MBWA system. As of this writing, Nokia Siemens Networks proposed Long Term HSPA Evolution (LTHE) which could offer peak data rates of more than 650 Mbps (6 times faster than ITU-approved 4G standard!) and is backwards-compatible with WCDMA and HSPA.