China Mobile Ltd. has delayed its massive 4G LTE-TDD tender -- worth billions of dollars and one of the industry's biggest -- while it decides whether to upgrade from 3G or install new network kit. (See China Mobile Seeks 4G Small-Cell Advantage.)This is more than just a technical issue. An upgrade from the existing 3G infrastructure would favor the incumbent TD-SCDMA vendors -- Huawei Technologies Co. Ltd., ZTE Corp. and state-owned Datang Mobile Communications Equipment Co. Ltd. A new build would put foreign vendors such as Alcatel-Lucent, Ericsson AB and Nokia Siemens Networks on a level playing field with their Chinese rivals.The key decision facing China Mobile's executives centers on spectrum. They must choose whether to base the operator's rollout on an upgrade from the existing TD-SCDMA network using F-band spectrum (1880-1920), or deploy new radio access network (RAN) equipment in the D-band (2570-2620).Analyst Earl Lum, president of EJL Wireless Research LLC, says the carrier will have to give preference to the D-band because it enables roaming, a feature glaringly absent from the TD-SCDMA network. But, he added, eventually both bands would be needed, as this would allow for "90MHz of bandwidth vs. 40 or 50MHz individually."To date China Mobile has rolled out LTE-TDD trial networks in 13 cities, with contracts allocated among five vendors -- Huawei, ZTE, Ericsson, Nokia Siemens Networks and Alcatel-Lucent. The new tender is for its major buildout ahead of commercial launch, expected in the second half of the year.The tender, for 200,000 base stations in 100 cities, was originally planned to start in April, but is unlikely to be called until June. Estimates of its value range wildly, from US$6.75 billion, according to Reuters, or as much as $30 billion, according to local business press reports. Ericsson China executive vice-president Eric Feng told a media briefing Wednesday that China Mobile executives "hadn’t reached a final consensus" on the rollout strategy. But he said that in the current trials, using the F-band spectrum, the upgraded base stations suffered from interference and limited network functionality. Given these issues, and China Mobile's tight timetable, Ericsson believes that the "new build is the best option." That option, of course, is the one that is most likely to benefit Ericsson.— Robert Clark, contributing editor, special to Light Reading