無線4G的慢慢長路

Don't hold your breath waiting for the next wireless broadband technology. It will be a few more years before we have access to broadband Internet services that are truly wire-free. However, the development of Long Term Evolution (LTE), the evolving 4G technology for high-speed data access over cellular networks, will be under the gun in 2009.


Despite a host of uncertainties about the pace of rollout for this flavor of mobile broadband, IC vendors are busy getting their designs ready for this emerging 4G technology.


Players in the consumer electronics sector want to avoid the mistakes encountered during the rollout of 2.5G and 3G networks when interoperable handsets were not available in a timely fashion for the upgraded networks.

LTE will become the first truly global standard for mobile data, with launches for data cards in 2010 and handsets in 2011.

For LTE, the issue is more likely to be ensuring that LTE-capable devices are available for embedding into PCs and mobile computing devices rather than phones, since the initial emphasis is bound to be on high-speed data transfer rather than better and wider voice coverage. Terminal availability has too often been blamed for slow rollouts, due to endless options that have made the poor handset designers' and manufacturers' lives difficult.


This won't be easy since the standardization process for LTE has some way to go, even though the important Release 8 for the technology, being devised under the auspices of the 3GP standard group, is due to be finalized this month. But as the industry is well aware, this will not be the end of the story.


There is too much uncertainty regarding the frequency ranges at which LTE will operate--anywhere between 900 MHz to 2.6 MHz. Network topology is also a subject of debate among operators: Will it be targeted at hot-spots only? Will LTE be a rapid replacement for 2G or 3G? Will it be for data only, or data and voice from the outset?


For chip designers, this means the need for greater flexibility and compatibility. Why? LTE is not the only game in town for 4G; mobile WiMAX is slightly ahead of the game. Chip, customer premises equipment (CPE) and terminal designers will need to ensure a single solution for broadband wireless, deploying baseband and RF that support both environments.


We should not expect major LTE rollouts before 2010 for use with data cards and 2011 for handsets. The bottom line: LTE is specified to support multiple bands in both time division duplex (TDD) and frequency division, duplex (FDD) modes, and will evolve to be the first truly global standard for mobile data.