Japan's UQ Communications is providing a model for other WiMAX operators to follow as it lays out a plan to offer 1 Gbps data speed by 2017 using WiMAX Advanced technology while maintaining backward compatibility for the 4.27 million customers already using its older 802.16e WiMAX services, according to a white paper sponsored by the WiMAX Forum.
In July, KDDI subsidiary UQ was awarded 20 MHz of TDD spectrum in the 2.6 GHz band, which is adjacent to its existing 30 MHz spectrum holding. Subsequently in October, UQ switched on WiMAX 2.1 technology, which it has branded as WiMAX 2+. The service offers download speeds of up to 110 Mbps and is compatible with TD-LTE. However, UQ is not authorized to offer LTE technology in the 2.5/2.6 GHz bands.
Going forward, the operator expects to adopt WiMAX Advanced features such as carrier aggregation, 256 QAM and 8x8 MIMO as it targets delivery of 1 Gbps download speeds by 2017.
WiMAX 2.1 technology also "provides a path to convergence with LTE TDD where operators may benefit from the larger economies of scale associated with a larger ecosystem of TD-LTE devices," said the white paper, which was prepared by Berge Ayvazian, senior consultant with Heavy Reading.
In October 2012, the WiMAX Forum announced that its WiMAX Advanced network evolution roadmap beyond WiMAX Release 1 and Release 2 would accommodate harmonization and coexistence across multiple broadband wireless access technologies. The group's announcement basically acknowledged that many WiMAX operators intended to deploy additional technologies such as LTE Advanced, including both the TDD and FDD flavors of LTE.
This figure, from the WiMAX Forum, illustrates the technology roadmap and the evolution of the 802.16 standard mapped to WiMAX Advanced.
The Heavy Reading white paper noted that some Broadband Wireless Access (BWA) service providers using WiMAX want to harmonize their networks with TD-LTE. However, the paper said, "most of these WiMAX operators do not have the capital or spectrum to allow them to make this transition at their own pace without disrupting their existing services and subscribers."
Therefore, the best option for these operators is apparently to leverage WiMAX Advanced technology to support new TD-LTE devices that can complement existing WiMAX devices. However, some operators are being hindered by regulatory restrictions. For example, some BWA spectrum licenses prohibit service mobility and would not allow licensees to support TD-LTE devices on a WiMAX Advanced network.
Meanwhile, in South Korea, which once hoped to jumpstart the WiMAX ecosystem by licensing operators to use its related WiBro technology , the Ministry of Science, ICT and Future Planning (MSIP) last fall outlined a new policy to help WiBro licensees migrate to TD-LTE. Regulators expect the nation's 1 million-plus WiBro subscribers will transition to WiMAX Advanced.
"The MSIP provided support for WiMAX Advanced, so existing WiBro services, which are serving special purposes in such fields as national defense, can exist in a niche market, while expanding to overseas markets by means of network establishment and technological development," the white paper said.
The MSIP has also it will release during 2014 a national plan for TD-LTE market development.
Of course, the U.S. poster child for the WiMAX-to-LTE migration is Sprint (NYSE:S), which still serves millions of subscribers via the Clearwire WiMAX network. "With an average of 120 MHz of 2.5 GHz TDD spectrum nationwide and access to new capital from SoftBank, Sprint can afford to use some of its Clearwire spectrum to manage this transition where mobile WiMAX and TD-LTE will co-exist over a period of two years or more," the white paper said.
More than 477 operators have deployed WiMAX networks in 150 countries, covering some 1 billion people and providing wireless broadband services for more than 25 million customers.
- see this white paper (PDF)
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