At present, in the choice of TD-LTE development path, the focus of the discussion has actually been condensed into a tangled spectrum selection question: do you want F or D?
From the spectrum point of view:
F-band loss is small, D-band is clean
At present, F-band and D-band are available for China Mobile's network construction, and F-band (1880MHz ～ 1920MHz) has two schemes based on the original TD-SCDMA base station upgrade and co-site new construction. The D frequency band is the global mainstream TD-LTE frequency band determined by the International Telecommunication Union, and the Ministry of Industry and Information Technology has also clarified that a total of 190MHz frequency (2500MHz ~ 2690MHz) in this frequency band is used for TD-LTE. F-band is the main frequency band of China Mobile's TD-SCDMA.
As a result, China Mobile's 4G network has a variety of programs such as F-band, D-band and F / D hybrid networking. For equipment manufacturers, the D frequency band is a new method, and everyone must start from the beginning, and whether the F frequency band is upgraded or newly built will fundamentally affect the interest pattern of the equipment manufacturer.
The D-band has more space loss than the F-band, and the number of sites using the F-band networking in the entire network will be less than the D-band. However, the existing F-band TD-SCDMA and PHS that have not been completely withdrawn from the network are occupied, while the D-band has a rich and clean 190M bandwidth. Therefore, from a technical point of view, building a network in the D band is like drawing on a white paper, which is relatively difficult. Building a network in the F band is like drawing on a ready-made one. Looking forward and looking back, the difficulty of network construction is relatively high, especially the difficulty of upgrading is greater than that of new construction.
From the perspective of cost performance:
F-band upgrade saves money, D-band industry chain is sound
For a brand-new wireless network, the operator must first solve the coverage problem. As we all know, China Mobile has invested a lot of money in TD-SCDMA, the TD-SCDMA network has a certain scale, and as early as the introduction of the F-band in the fourth phase of China Mobile ’s TD-SCDMA bidding in 2010, China Mobile has already specified in the bid It is proposed that the F-band equipment needs to support the smooth upgrade of TD-LTE, that is, China Mobile made a technical foundation for the F-band upgrade of TD-LTE three years ago. More than 75% of China Mobile's existing base stations already support the F-band TD-LTE upgrade. If the existing TD-SCDMA network resources are fully utilized, not only can the trouble of re-networking be saved, but also a lot of money can be saved.
The D frequency band is the TD-LTE frequency band divided by the ITU. Almost all mainstream equipment manufacturers have relevant equipment support and have a more complete industrial chain. In the long run, the D-band is a strategic spectrum resource that China Mobile must seize anyway.
If the construction of China Mobile's 200,000 base stations this time is mainly F-band upgrade, it means that equipment vendors who have obtained a large share of the TD-SCDMA and TD-LTE test networks in the early stage will continue to have market and share advantages, and will continue to TD-LTE occupies a dominant position. If China Mobile chooses to build a new network in the new D-band, then all equipment vendors will compete on the same starting line.
From a global perspective:
D-band is more conducive to internationalization
As we all know, an important idea for China Mobile to launch TD-LTE is to avoid the embarrassment of the 3G era and make TD-LTE an international standard. To this end, it has launched the TD-LTE Global Development Initiative (GTI). So far, GTI has 51 operators and 44 manufacturers supporting TD-LTE; there are 14 TD-LTE commercial networks and 63 TD-LTE trial networks in the world; Hong Kong, China launched the TD-LTE / LTE FDD converged network.
In consideration of international promotion, the development of the TD-LTE industry chain lags behind that of LTE FDD. If a certain industrial chain is relatively backward, it may cause related equipment manufacturing, testing, support and other companies to have low investment enthusiasm, unable to produce scale effects, higher network construction and terminal costs, fewer optional terminal products, and user experience on terminals Poor, etc., the pace of internationalization will be more difficult.
At present, although TD-LTE has started commercial use in Japan and India, it is relatively small in scale and cannot form a force that affects the development of the industry chain. Some members of the TD-LTE Development Initiative made it clear that only when a big country like China "takes the lead" to form a demonstration effect, TD-LTE can rely on the rapid development of the market to form a scale, can reduce the cost of commercialization as soon as possible, and can be on the industrial chain. Only downstream plays a catalytic role, can TD-LTE form international achievements. To achieve economies of scale, it is clear that it is more realistic to implement the D-band specified by ITU.
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