Is that the death knell I can hear sounding for WiMAX? Not quite. The wireless technology has taken several body blows recently, but it should survive.
Of these blows, erstwhile WiMAX champion Clearwire’s decision to trial LTE technology is probably the most damaging, along with the news that some of the companies that have secured 2.3 GHz spectrum in the potentially enormous Indian market plan to use LTE rather than WiMAX.
WiMAX has been put on the back foot by the momentum building behind LTE TDD, the LTE variant that uses the same unpaired spectrum allocations. Although mobile WiMAX reached the market earlier than LTE, it has failed to gain a strong foothold and its modest achievements to date have mostly been overshadowed by the rapid growth of HSPA and now HSPA+, as well as EV-DO. By the end of 2010, there will be 8.7 million mobile WiMAX connections worldwide, according to Maravedis, compared with more than 380 million HSPA connections, according to Wireless Intelligence.
So, why hasn’t mobile WiMAX gained more traction? On paper, it has considerable promise – it uses many of the same advanced technologies as LTE, including OFDM and MIMO on the radio interface. But in practice, live WiMAX networks aren’t performing any better than HSPA+ networks. Clearwire says its WiMAX service offers average mobile download speeds of 3 Mbps to 6 Mbps, while independent tests have found that T-Mobile USA’s HSPA+ network is delivering average download speeds of around 5 Mbps. In Stockholm, TeliaSonera’s commercial LTE service delivered an average downlink speed of 33.4 Mbps in recent tests by IDG News Service.
Incompatible and In the Cold
Moreover, unlike HSPA+ and LTE, WiMAX wasn’t designed with compatibility and co-existence with mobile operators’ existing GSM, CDMA and 3G networks at its core, meaning that a call or data session can’t necessarily be handed-over between a conventional mobile network and a WiMAX network, as a subscriber moves in and out of coverage areas. Given that context, the market for WiMAX has really been limited to so-called green-field operators, as it would have been an expensive U-turn for any operator to move from GSM or 3G into WiMAX, instead of simply upgrading to HSPA. For similar reasons, a step from CDMA-2000 into WiMAX would effectively be a massive gamble on customers being prepared to put up with potentially dropped calls and data sessions when they moved out of areas of WiMAX coverage.
As WiMAX isn’t a viable upgrade option for most existing mobile operators, it has been very difficult for vendors to get the economies of scale necessary to develop a wide selection of mass-market WiMAX devices. While HSPA has an ecosystem made up of several hundred equipment manufacturers offering more than 2,000 HSPA-capable devices, many vendors have turned away from WiMAX and towards LTE, and now some hitherto WiMAX operators are following suit.
Mash-up or Mess-up?
WiMAX’s incompatibility with existing mobile networks is just one of the reasons it hasn’t reached its apparent potential. In an age when openness and diversity, mash-ups and application development are creating a vast range of end-user services, it is easy to forget that mobile telecoms is a huge global success because of tight adherence to standardized technologies.
By contrast, early WiMAX networks have been deployed using a variety of implementations which have not always been compatible with one another and have held varying degrees of compliance with the 802.16 specifications. All of these implementations have been swept up under the WiMAX banner, but having a single name for a disparate collection of technical implementations does not replicate a standards-based ecosystem. This fragmentation creates an R&D headache for device manufacturers as they often need to adapt equipment for specific operators and specific networks. In trying to get ahead of LTE by arriving early and exploiting the resultant time-to-market advantage, WiMAX has shot itself in the foot.
Now, WiMAX finds itself in a precarious position. The vast majority of the major mobile operators in the world have made public statements of intent to move to LTE and they are making sure that this technology is deployed in a consistent way that will enable the ecosystem to achieve economies of scale. The years of experience that these operators have with deployments of 2G and 3G technologies mean that the LTE pioneers are unlikely to make the same mistakes as their WiMAX counterparts.
The breadth and depth of LTE’s global support is very ominous for WiMAX, but I do see the 802.16 technology having a future, primarily in scenarios where mobility and interoperability are a secondary consideration. These could include acting as an alternative to fixed lines in areas that are difficult and expensive to reach with ADSL and as a backup service in case a fixed line fails. WiMAX is also sometimes used to provide backhaul links for mobile base stations and it should continue to have a role in that market.
So, WiMAX will live on, but not as a significant rival to HSPA or LTE.
Dan Warren is director of technology at the GSM Association (GSMA).
Filed Under: Infrastructure