WiMax experience and SON capabilities crucial, says Motorola
Motorola will exploit its experience in deploying OFDM-based networks as it competes for LTE business from early operator adopters, according to its director of product management, Rock Mostaert.
Mostaert said that experience of deploying live networks in real conditions will give the vendor a competitive advantage, despite claims that the latest generation of base stations from the likes of Ericsson and Nokia Siemens Networks are upgradeable to LTE, or LTE-ready.
"What does upgradeable to LTE mean?" Mostaert questioned. "When you deploy MIMO, you have to do so at the right frequency bands, you still have to go to the site to deploy additional power, and add radios in that spectrum. At a best case you can re-use the base band, assuming you have the processing power.
"And then there's the behaviour of the network within a multi-user environment. When you deploy in a real environment you find things don't behave like they do in the lab. There's a lot of complexities and nuances that you work back into the schedulers. Also, the general optimisation is different from CDMA and TDM networks. We have found in deployments that IP backhaul is sometimes overlooked, that is critical and that's got to be there otherwise the benefits are not reliable. QoS also has to be enabled end to end if you want to offer the different services that LTE has the capability to offer."
Mostaert also said that the ability of LTE networks to be truly self-optimising will be crucial to meeting operators' cost-per-bit demands – and will be another area where Motorola's OFDM knowledge can offer advantage. Self-optimising networks (SONs) mean that the nework elements themselves can use in-built software to optimise network coverage and capacity as required, saving the operator manual analysis and configuration, or even site visits. As LTE sites are not likely to map onto existing 3G cells, this aspect is likely to be crucial to the operational efficiency of LTE networks.
"The expectation is that the cost per bit target for NGN is 10x over time, so that over time their cost for that network is 10x per bit cheaper than today. Speaking for ourselves, we have been putting a lot of effort into SON, after listening to operators who are telling us that is a key requirement to lower costs. So we have a complete roadmap on SON, showing operators screen shots of how it would work and how may hours it would save using this method versus how they used to do it"
Although all the main vendors are developing SON techniques, Mostaert contends that Motorola has an advntage because, "SON is only as good as the expertise you are relying on. We have knowledge of planning, deploying and optimising OFDM/MIMO networks, and we can take that knowledge and automate it."
But John Cunliffe, CTO for Ericsson UK, said that getting to grips with OFDM and MIMO technology had presented no problem for Ericsson, a company with no existing WiMax development path of its own.
"Not at all," he said, when asked if Ericsson had been challenged by the new technology.
Cunliffe said that Ericsson is confident it has built the trust with operators to win market share. And he added that people seeking to predict what will happen in the LTE market are being "over optimistic".
For Cunliffe, there are still too many unknowns, such as what will happen around spectrum. He said that 2.6GHz spectrum auctions are going to be very difficult to preduct, and could end up with operators buying TDD spectrum very cheaply, for example, as there is a rush for 2.6GHz spectrum to support HSPA+ services in FDD spectrum.
He also said that there may be a case for fixed or cable operators to extend broadband coverage to rural areas, using digital dividend spectrum to access these areas much more cheaply than laying out new fibre. In that case, he said, the focus would be not so much on mobility or capacity, as providing coverage, skewing investment cases for LTE.
But Cunliffe agreed that SON and the ability to offer QoS and class of service will be important differentiators for mobile operators. Ericsson to is developing its 4G equipment to be self-optimising.
"Operators have got to get away from the ‘up to' numbers" he said. "I think the public are onto them there, and they will become more realistic." QoS capabilities in the LTE standard would allow operators to offer more accurate guarantees around levels of service and data rates, he said.