For the world's biggest mobile operator (by subscriber numbers), 4G still offers a lot of mileage.
"4G is very popular globally. This infrastructure should provide a significant part of what people need for a long time," said Chih-Lin I, CMCC chief scientist, Wireless Technologies, China Mobile Research Institute (CMRI), speaking last week in London at the 5G Huddle.
So a move to 5G needs to bring significant benefits in order to be worthwhile.
For China Mobile, 5G should usher in new approaches to planning, optimizing and building networks that will help make the provisioning of apps and services more efficient and, thus, improve profitability. "The business model will be key in the future. We don't need 5G to do telehealth," as it can already be done on 4G, according to Chih-Lin I.
China Mobile has a large and rapidly growing customer base, increasing the need for more efficient network design. As of June 2014, China Mobile had more than 700 million 2G customers supported by 900,000 GSM/GPRS/EDGE basestations, more than 238 million 3G customers supported by 0.5 million TD-SCDMA basestations, and more than 13.9 million 4G (LTE TDD) customers served by 410,000 million basestations. And 4G is set to grow: The operator's 4G customer base reached nearly 30 million by the end of August, and it expects to hit 50 million LTE TDD users by year-end.
So, apart from further customer growth, what happens next? The arrival of 5G should enable the industry to move away from "a classic cellular idea," according to Chih-Lin I. "In the past we talked about 1G, 2G, 3G and 4G in a quite narrow sense of next-generation mobile standards that is defined by standards bodies such as 3GPP. But going forward the collective 5G vision all of us have ... should be properly renamed 5G Era vision."
The "5G Era" encompasses a rejig of current approaches to antennae and infrastructure design, as well as a rethink on signaling, spectrum management and the use of cells: Chih-Lin I refers to it as "a string of pearls."
Like other operators, China Mobile wants networks to use less energy, and provide software-based services more efficiently and easily over lower-cost hardware. The network "used to be hardware centric… but that made us very inflexible," says Chih-Lin I, who favors greater use of "consumer-grade components."
Meanwhile, new approaches to signaling will be key to improving app performance, she believes. "Some apps are inefficient on the [current] network. We would like the signaling protocol to be designed for a new architecture to take into account the type of app, and the local traffic loading situations," she added.
China Mobile is also busy rethinking basestation design. On its wish list is smaller, lower-cost basestations that look, for example, like attractive tiles that may be more easily accepted by building owners and town planners than today's small cell designs. And "in the future we may have data-only micro cells… we may separate the uplink and downlink, and it may be that we have different basestations" for downlink and uplink, noted Chih-Lin I.
Many of these changes will be gradual. So when will we know we've arrived in the 5G era? One measure might be "high definition everywhere, and that would mean a 65 Mbit/s speed rate," she suggested.
— Joanne Taaffe, special to Light Reading