Will 4G Fix Wireless Voice Quality?
- — 14 May, 2010 23:44
"Can you hear me now?" As much marketing hype as 3G wireless networks have received, the fact remains that customers of all the major wireless providers are frequently frustrated with their service's poor voice quality and dropped calls. With 4G looming on the horizon, can we look forward to better voice quality?
What Goes Wrong With 3G
To answer that question, it helps to first understand the flaws or inadequacies of 3G that cause the dropped calls, latency, and line-noise issues.
"The larger the footprint from a given site (achieved by increasing the transmit power or the height of the antennas), the more interference this site will cause to an adjacent site," says Paul Carter, president of wireless research company Global Wireless Solutions. Cell signals can also be impeded by topography such as buildings, trees, and hills within the cell zone servicing either party on a call.
4G networks like WiMax or LTE use superior MIMO (multiple-input, multiple-output) antenna technologies that help alleviate some of these issues. MIMO won't improve the sound quality of voice calls by itself, but using multiple antennas improves signal quality and ensures a more consistent and reliable connection.
More important, 4G technology can connect far more calls and data connections than 3G can, using the same amount of wireless spectrum. So the available bandwidth pipeline in 4G networks is significantly larger for individual users and devices.
One Service per Network
4G networks should improve voice quality to some degree even if the carrier puts most of its network resources behind data service. For example, if the high bandwidth demands of broadband data are allocated to the emerging 4G network, the 3G network is freed up to support voice. The increased capacity will lead to clearer, more stable voice calls that don't have to compete with data service for bandwidth.
"We expect that, initially, our 4G LTE network will be used primarily for data, with the majority of voice traffic going over our 3G network," says AT&T spokesperson Jenny Bridges. This will be a welcome development for AT&T, which scored worst among all major carriers in a recent study of cellular voice quality.
AT&T says it will begin testing 4G later this year, and it expects initial deployments to begin in 2011. "Our initial plans for LTE deployment call for the service to be used over new spectrum that we've set aside for the technology," Bridges adds.
Verizon currently uses a similar approach with its 2G and 3G networks. A Verizon spokesperson explains that Verizon manages voice on a 2G network and data service on a 3G network, so that it can optimize each service independently. Verizon won't say whether it intends to follow that same approach when its 4G LTE network begins lighting up later this year.
Is HD Voice Finally Coming?
The higher bandwidth and network capacity of 4G networks may also increase adoption of HD voice. HD voice calls sound as if the two parties on the call were sitting in a room next to each other having a conversation, rather than battling to talk over each other and missing half of the conversation due to overlap and latency. The increase in clarity and the decrease in line noise and call drops has led Skype users to talk almost 50 percent longer than callers using traditional voice networks, according to Skype CTO Jonathan Rosenberg.
Still, 4G networks may have to be ubiquitous before HD voice becomes widely used. As the Verizon spokesperson notes, "4G brings a bigger pipe, but it is the networks we will hand off to -- there is no value in HD voice if the called customer is on 2G cellular or landline." Also, the Verizon rep says, mobile handsets will need to build in improved speakers and microphones to enable the HD voice capability.
With streaming audio and video, and even videoconferencing coming to mobile devices, the demand for data bandwidth will likely continue to grow exponentially. This demand for data capacity is forcing providers to expand their network infrastructure, and voice quality may improve as an unintended fringe benefit.