AT&T's Rinne weighs in on VoLTE, small cells and LTE broadcast trials

AT&T Kris Rinne

Kris Rinne

with Kris Rinne, senior vice president of network architecture and planning at AT&T Labs

LAS VEGAS--AT&T Mobility (NYSE:T) used the 2014 Consumer Electronics Show as the backdrop for its annual Developer Summit, where it brings together developers from around the world to help them make innovative services for the company's network, devices and platforms.  During the developer summit, FierceWirelessTech Editor in Chief Sue Marek sat down with Kris Rinne, senior vice president of network architecture and planning at AT&T Labs, to get a status report on some key initiatives for the company such as voice over LTE, HD voice, small cells and more. Here's an excerpt from that interview.

FierceWirelessTech: Where do you stand with HD Voice and VoLTE? These were both initiatives you said you were working on in 2013.

Rinne: We are still in testing in terms of the initial markets. I would call it the final stages of testing. The timeline will boil down to when we have it to the same quality as our circuit-switched. It will depend upon accessibility and attainability.

FierceWirelessTech: Is the ASUS phone that AT&T talked about this morning [the ASUS Padfone X, an LTE-Advanced smartphone that is exclusive to AT&T] the first VoLTE phone?

Rinne: We didn't talk about timelines. It will be VoLTE-capable at the right time. 

FierceWirelessTech: So you are seeding the market with devices?

Rinne: Yes

FierceWirelessTech: When it comes to carrier aggregation, you said you were testing it in 2013. What are your plans for 2014?

Rinne: We launched our first device, the AT&T Unite, it's a puck that uses carrier aggregation. We are complete with the validation from an infrastructure standpoint. As we implement second carriers in the markets, meaning add a spectrum band of LTE, typically either AWS or 1900, we will be able to take care of that with carrier aggregation. It will be rolled out over time as we add capacity in the network.

FierceWirelessTech: So it's about bringing all these spectrum bands together?

Rinne: Yes, we are focused on the 1900 MHz and 700 MHz and AWS spectrum. Carrier aggregation is confusing because we are all taking about different spectrum bands.

You have to have your infrastructure capable and ours was LTE ready. Then as you add the second band and you have to allow it to aggregate. And then you have to have devices that support aggregation. And then if you want speeds to increase, you have to have backhaul that can handle it.

FierceWirelessTech: It always comes back to backhaul. And the backhaul has to be compatible as well, right?

Rinne: Yes, but you are always adding more backhaul to keep up with capacity.

FierceWirelessTech: There is still debate about how effective small cells are in the network. Is AT&T still a big advocate for small cells?

Rinne: Yes, what we have launched to date are small cells that are UMTS/HSPA compatible. We are still working with supplier community for a multi-standard that would allow us in the same platform to have LTE/HSPA and Wi-Fi. We are on the development curve for that. We built a lot of the tools in terms of how to leverage the knowledge you have in the network to optimize the placement. You have to be accurate with the placement of the cells to be accurate because they radiate differently so you have to solve those issues. We have deployed several small cells from capacity augmentation to coverage augmentation. We've deployed small cells indoors and outdoors. And we are seeing solid performance.

FierceWirelessTech: Some of the criticism directed to small cells has been that you need backhaul and there isn't going to be backhaul. And you also need power. All these elements make it more complicated and more costly.

Rinne: Yes, there are those processes and even if we own the backhaul, the telephone poles don't have street addresses, which makes it difficult. We are building the tools and processes associated with those things as well.

FierceWirelessTech: I think there are companies looking at this as an opportunity and it reminds me of all the building owners that thought they would charge companies to put antennas on their roof back in the LMDS [local multipoint distribution services] and MMDS [multichannel multipoint distribution services] days--but that didn't end up being the business opportunity some had hoped for. Is this another iteration of that land grab mentality?

Rinne: There might be some of that. But it will take partners in terms of negotiating the right of way for connectivity to the poles and lampposts if we aren't the landline company in the area. It will take an ecosystem. But our driver is to reduce the costs and improve the quality of the experience. And managing it so the ecosystem doesn't get out of hand is important.

We are partnering to go to market in unique ways and building those relationships and choosing those partners.

FierceWirelessTech: The Super Bowl is coming up. One of your competitors is talking about LTE broadcast and they plan to do something with that around the Super Bowl. Are you considering LTE broadcast?

Rinne: LTE broadcast is something we are looking at. We have not announced any timelines or trials but it is something we are considering. We think it's a good way to efficiently address video demand that we see growing in the marketplace. I would definitely anticipate it will be part of our product portfolio.

FierceWirelessTech: I know you have said that you want to be absolutely sure that when you migrate customers to VoLTE that the service is as reliable as circuit-switched voice. But why is it taking so much longer than people had anticipated to migrate to VoLTE?

Rinne: It's a brand new SIP stack. It's a brand new radio access network and you have all these new parts of the IMS architecture. Plus it's changing your interface for E911 and CALEA and the regulatory pieces of that. Plus we are driving the handover scenario back to the circuit switched.  Optimizing all of that end-to-end is what we are continuing to do.

FierceWirelessTech: You are the chairperson of 4G Americas again. Last year you were the chairperson of ATIS. Are these boards and organizations helpful?

Rinne: They are very well run organizations, ATIS and 4G Americas. As the leader you are doing more steering rather than peddling. They are beneficial from the standpoint that there are issues that we are trying to get done and you need a commonality--across U.S. and international--and you can work on those issues with the whole ecosystem but in a smaller, more focused forum.


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