If HSPA can have a plus, why not WiMax?

Some of WiMax’s leading operators want their chosen technology to have a bit more zing. This week at the WiMax Forum Global Congress in Amsterdam they presented their proposal for WiMax-Enhanced, an upgrade to current WiMax infrastructure that will greatly improve mobile broadband capacities and allow operators to make better use of their spectrum.

Operators Clearwire (NASDAQ:CLWR) and UQ Communications teamed up with vendors Alvarion (NASDAQ:ALVR), Beceem Communications, Fujitsu, GCT Semiconductor, Hitachi, Huawei, Intel (NASDAQ:INTC), Motorola (NYSE:MOT) NEC, Samsung, Sequans Communications and ZTE to hash out an interim upgrade for WiMax that operators can deploy before the next generation of the network technology emerges with WiMax 2. Similar to the high-speed packet access plus (HSPA+) upgrade for 3G networks, WiMax-Enhanced will primarily require a software upgrade to the base station, with an optional antenna upgrade adding additional capacity to the network.

The upgrade, however, isn’t requiring the WiMax sector to go back to the drawing board. The technical enhancements the working group is promoting are already laid out in the Institute of Electrical and Electronic Engineers' 802.16e standards — they just haven’t been implemented into the WiMax Forum’s certification profiles. The Forum has agreed to develop a certification program for the new enhancements by the end of the year, which could lead to the first WiMax-Enhanced products by the beginning of 2011 — just in time for UQ and Clearwire to use their performance benefits to compete against new long-term evolution (LTE) operators in Japan and the U.S.

At the Congress, the Forum focused on the home base station as well as the macro site, announcing with the Femto Forum the publication of the first WiMax femtocell standards. The Forum plans to begin certifying its first femtocells in 2011.

For the macrocell upgrade, the principle technical enhancements are an increased range and cell-edge performance through improved error correction techniques in the link budget and better interference management techniques that will allow operators to adopt frequency reuse factor one topologies. In English, that means operators will be able to use the same frequencies in adjacent cells, rather than alternate cell by cell in order to minimize interference, as they do today. By incorporating both of those enhancements a operator could boost spectral efficiency and overall network capacity by 40% without building any additional cell sites or installing any additional base stations.

For an operator like Clearwire, those enhancement could be a major advantage in the future, as capacity demands increase on its network. Currently Clearwire is in such a strong spectrum position it has little need to worry about spectrum reuse. It’s typically running three 10 MHz channels per site, but given that it has more than 100 MHz in most markets, it can easily alternate frequencies. But Clearwire has also committed to maintaining its unlimited data policies well into the future, even though its average customer is consuming 7 GB a month and climbing. As Clearwire maxes out its current WiMax carriers, it could start stacking carriers onto cell sites that use the same frequencies of carriers on neighboring cell sites, enjoying a considerable boost in capacity without having to split cells, deploy more sites or find new spectrum.

“We’re committed to constant innovation, and these enhancements to the 802.16e standard will increase our ability to meet the incredible demand for super-fast mobile Internet both in the home and on the go,” said Ron Marquardt, vice president of technology for Clearwire, in a statement.

The working group has proposed, and the Forum accepted, a further set of enhancements called WiMax-Enhanced feature set 2, which could increase overall network capacities by 70% and double the peak data rates available to individual devices but would require new equipment and more elbow grease at the cell site to implement. The second phase mirrors HSPA+ in that it adds multiple-input/multiple-output (MIMO) antennas to the site, except in the case of WiMax downlink antennas, which would increase from two to four. The extra antennas would allow for MIMO beamforming, a technique first proposed by Navini Networks. Cisco Systems (NASDAQ:CSCO) bought Navini in 2007 but failed to capitalize on its technology, canceling its WiMax product line earlier this year.