The Road to 4G
From the November 2008 issue of Microwave Journal.
In 2008, the road to 4G has cleared a bit, with Ultra-mobile Broadband (UMB) left publicly by the roadside. However, the two remaining “4G” technologies, LTE and WiMAX, still present much speculation and confusion, InStat reported.
Generally, “4G” technologies are considered those which are expected to meet the ITU’s IMT-Advanced’s requirements, i.e. LTE and IEEE 802.16m WiMAX. Both of these are based on OFDM and offer the potential for download speeds of 100 Mbps and upload speeds of 50 Mbps. Both 4G technologies, talking from the perspective of 100 Mbps technologies, are far from being commercially deployed.
However, 802.16e Mobile WiMAX (802.16m’s slower predecessor) is starting to come on the scene, with Clearwire expected to launch its network in September 2008. For this reason, LTE proponents have jumped up their efforts to speed up development.
Several factors are expected to affect the rate of adoption of LTE and WiMAX over the next three to five years:
- All of the world is watching the Sprint-backed Clearwire Mobile WiMAX network roll-out. The success of this roll-out is expected to have a huge effect on whether large worldwide carriers will roll out Mobile WiMAX. Launch is scheduled for 4Q08.
- Verizon Wireless has chosen LTE as its 4G technology of choice instead of WiMAX. Verizon Wireless, like Sprint, had been a strong candidate for WiMAX adoption, due to its core CDMA network. Its decision puts a damper on the assumption that carriers with CDMA networks will choose WiMAX; on the contrary, now the assumption is that most will choose LTE. The company is also targeting an aggressive roll-out of LTE in 2010.
- HSPA may turn into 802.16e WiMAX’s true competitor, as HSPA roll-outs increase worldwide, and carriers look to HSPA Evolution to push network throughputs to 20 Mbps and beyond.
- Edge Evolved may come on the scene in regions where WCDMA has not yet been deployed by GSM operators, offering a fairly inexpensive and easy upgrade with promising throughput gains. Carriers’ decisions to adopt Edge Evolved may delay these carriers’ upgrade to WCDMA/HSPA, and furthermore, LTE.
- Carriers that have rolled out HSPA are more inclined to roll out HSPA Evolution, which offers high throughputs of up to 40 Mbps. This is expected to delay the beginning of commercial LTE roll-outs until the 2012-2013 timeframe.