Developer Opportunities with CLEAR WiMAX 4G: Clearwire’s initiative for apps development for WiMax systems

IEEE ComSoc SCV February 10th, 2010 Meeting Report

“Developer Opportunities with CLEAR WiMAX 4G”

This very informative and exciting meeting drew a large audience of over 85 attendees. Those present heard directly from Clearwire’s about their Silicon Valley Innovation Network (based on IEEE 801.16e-2005/Mobile WiMAX) and tools that are being made available for CLEAR 4G applications developers. Representing Clearwire were Allen Flanagan, Manager, Silicon Valley Innovation Network, and David Rees, Manager, Developer and Partner Enablement. The event featured excellent presentation by both speakers followed by Q&A as well as a panel discussion where meeting attendees were able to ask questions not already covered in the talks. The presentations and subsequent Q&A were moderated by Sameer Herlekar, ComSoc SCV Technical Activities Director, while the panel discussion was chaired by Alan Weissberger, ComSoc SCV Chairman.

Presentation Highlights:

David Rees, in his talk on “Application Developer Enablement,” first provided some background on Clearwire and its network.  Clearwire was said to be a broadband wireless network provider currently operating in 25 markets and reaching 30 million people with the potential to cover 80 markets and reaching 120 million people by the end of 2010. (Note that “people” here refers to the total populace in these markets, not the actual number of Clearwire customers.) Dave told us that Clearwire’s “4G” WiMax network (following the IEEE 802.16e-2005 standard) operates nationwide in the 2.5 GHz spectral band with an average of 150 MHz spectrum available per market. The principal funding sources for Clearwire’s 4G network deployment plans include Sprint, Comcast, Intel, Time Warner, Google and Bright House Networks. In fact, Clearwire received over $3.2 billion in funding and resources from these sources in 2008 alone. Additionally, the talk elaborated on the benefits of the WiMax-based 4G network over the contemporary 3G networks based on EV-DO and HSPA in terms of higher data rates and spectrum capacities, stronger device mobility support, and amenability for low-cost deployment via an all-IP network. Specifically, based on results from drive-testing their network in Portland, OR over a 17-mile distance at an average speed of 35mph and a top speed of 55mph, Clearwire claims that their network’s performance is an order of magnitude superior to the 3G networks over the same route in terms of peak and mean data rates as well as network latency. Clearwire’s teams attained a peak data rate of 19 Mbps, a mean data rate of 6.5 Mbps and a mean latency of 83 ms during the drive testing.

Mr. Rees then shifted to Clearwire’s plans for Application Developer Enablement, i.e., the platform which enables (or, to be precise, which Clearwire seeks to enable) application developers and OEMs devise applications and services which leverage the enhanced speed and capacities of the 4G network. David Rees then explained Clearwire’s philosophy of an “open network for open devices”, where any WiMax-enabled device including those based in MIDs, camcorders, netbooks and smartphones will be able to access the 4G WiMax network. In fact, the devices do not even have to be necessarily provided by the carriers. However, they will need to be certified by the WiMax forum before they can be considered admissible on Clearwire’s 4G network.

The presentation then explained how, in order to support the “open network for open devices” paradigm and the mobile internet applications operating thereupon, appropriate application program interfaces (APIs) need to be made available to developers and service providers. These APIs need to be able to access the mobile device’s location information as well as be aware of the network itself, thereby providing a superior quality of experience to the end-user. Clearwire seeks to provide location information via APIs that employ a client/server service whereby applications can determine their own locations (“where am I?”), a server/server service which enables geo-fencing or tracking (“where are they?”), enabling location in browsers themselves including Chrome, Firefox and IE, and also by working with existing location providers to use WiMax for reporting location information. For example, a lightweight JSON/HTTP service allows client applications including browsers to query their locations and obtain their latitude/longitude information from the server. Clearwire is also working on adding direct support for Google Gears, Firefox and other browsers. Similarly, the server/server service employs the device’s IP address or MAC address to determine the device’s location. Network-awareness will be provided via Session Information and includes enhanced location awareness via triangulation, radio-signal quality information, as well as diagnostics collection and reporting such as round-trip time to each neighbor (future enhancement) and neighboring sector information (also a future enhancement). The session information is sought to be provided by a single, or common API, the so-called CAPI, which Clearwire is currently standardizing and promoting. As a matter of fact, CAPI 1.2.1 has already been implemented on a variety of chipsets including Intel’s WiMax-enabled laptops. Moreover, CAPI 2.0, which is currently being standardized, will (when available commercially) include such features as neighboring sector information, handoff notification and a list of applications requesting a particular quality of service (QoS).

Suggesting that Clearwire views mobile video as a major application for the 4G network-enabled mobile internet, the talk elaborated on Clearwire’s efforts to ensure a high-quality end-user experience by supporting in-network video optimization as well as session information provision to video clients, video servers and video service providers to help them optimize their transmission/reception performances.

The final part of the Developer Enablement portion of the presentation focused on QoS and its current status vis-à-vis Clearwire’s 4G network deployments. The talk explained that traffic streams such as video are specified to have a particular service-level in terms of throughput, latency (network delay) and jitter (delay variation). The network then identifies these streams and attempts to provide the desired service-level to each stream with a goal of minimizing the likelihood of network congestion while concurrently supporting different service-levels. At this time, while QoS has been implemented in Clearwire’s network, it will be offered to users only after Clearwire concludes its ongoing open-internet NPRM talks with the FCC and it’s (Clearwire’s) partners on when QoS-on-demand should be formally deployed. Additionally, Clearwire is yet to finalize its strategy with respect to load balancing (balancing QoS demands from a plurality of end-users), as well as network management once full QoS-on-demand becomes available, possibly in the third quarter of this year.

The Developer Resources section of the talk was presented by Allen Flanagan, where the 4G WiMax Innovation Network, also known as CLEAR was explained in detail. According to the presentation, CLEAR is a pre-commercial network deployed in parts of Silicon Valley including Palo Alto and Menlo Park, Mountain View and Santa Clara for testing mobile device-based applications. Registered service, application and content developers may make use of this service for free for the duration of the program. Noting that the CLEAR program encourages app developers to create applications which take advantage of the mobility aspect of the device, the talk pointed out that the Innovation Network is, however, not a testbed for hardware nor is it intended for end-users. When invited to suggest an example app for the 4G Innovators Network, Allen Flanagan outlined an application for public safety teams which could perform voice recognition and possibly translation. Such an app could be very useful for disaster-hit areas where local first-responders need to communicate with emergency workers who may not speak the native language. The talk concluded with an invitation to the audience members to receive free passes to the 4G WiMax Developer Workshop to be held in Santa Clara Convention Center on March 2nd of this year.

Panel Session:

The panel session, moderated by Alan Weissberger, addressed a number of issues which were raised even during the Q&A sessions following the speaker presentations. Both the Clearwire reps provided a wide-range of information on device and app certification, locations (stores) where the apps may be obtained, as well as the all-important question of QoS. During the panel discussion, audience members came to learn that:

There will be no special app store for CLEAR-developed applications. Clearwire welcomes apps purchased through stores belonging to their partners like Intel, Google, Apple and Palm.

Clearwire certifies devices approved by the WiMax forum and will certify only those apps which are provided by Clearwire; any other developed apps will not be certified by them.

Clearwire’s handheld WiMax device will become available later this year.

Network usage and available capacity will be monitored over time and adjustment of capacity will be made based on backhaul traffic statistics. While real-time capacity adjustments are not possible, Clearwire will leverage the 150 MHz of available spectrum to help meet any projected increase in user demand for capacity.

When pressed on whether Clearwire’s business model takes into account a point of network failure due to conflicting user demands for QoS, or whether Clearwire can guarantee that a fixed QoS will be supported by their network for a (statistical) percentage of communicating devices for a (statistical) fraction of the time, the Clearwire reps acknowledged that the QoS-on-demand issue is a major challenge to network planners and that they will relay the question to the their engineering teams as developer feedback.

When asked whether Clearwire’s future WiMAX enabled phone would use mobile VoIP or cellular voice, Clearwire’s Allen Flanagan understandably refused to answer as the product has not been officially announced. For speculation on what type of voice would be used on WiMAX handsets, please see:


Analysis and Opinion:

The 4G WiMax network being deployed by Clearwire as a means to enable the mobile internet is certainly a very strong response to the tremendous attention being accorded to LTE in recent months. Additionally, the 4G Innovation Network program, a.k.a. CLEAR is a clever approach to attract app and content developers by providing them with free access to the WiMax network prior to any commercial deployments. That the CLEAR program targets Silicon Valley is not surprising either, given the vast number of hi-tech innovations which have been born in the valley. With regard to air interfaces, Clearwire’s drive-testing results showed that the OFDM-based WiMax combined with 150 MHz of available spectrum can achieve significant mobility support for major bandwidth-hungry applications such as mobile video (we note, however, that Clearwire’s drive-testing was undertaken at off-peak hours to minimize any loading effects).

Many industry experts predict that mobile video is the killer application for the true mobile internet. This viewpoint does not seem to have been lost on Clearwire, given their emphasis on supporting mobile video on their 4G network. In order to support apps which feature mobile video as well as other applications, Clearwire will provide APIs which support RF awareness, location awareness and network awareness. On the crucial issue of QoS, Clearwire has enabled QoS in it’s networks even though it is not yet available to end-users, pending talks between Clearwire, it’s partners and the FCC.

The solid attendance for this meeting and the number and variety of questions raised by the attendees points to great enthusiasm among potential app and content developers to leverage the promise of Clearwire’s 4G network.

Besides the current unavailability of QoS guarantees to support applications like mobile video, the network’s ability to support multiple bandwidth-hungry applications from multiple users (numbering in the hundreds of thousands in some markets) is still an open question which Clearwire’s engineering teams will no doubt be actively engaged in to answer. However, Clearwire has undertaken notable steps in its quest to acquire a lion’s share of the mobile internet network operator market including enticing potential app and content developers and service providers to develop a plethora of mobile apps via the CLEAR program. It is now up to developers to unleash their creativity and devise apps which are innovative, timely and which truly provide end-users with a superior quality of experience on their mobile devices. Simultaneously, Clearwire needs to live up to it’s promise of providing a network which supports high mobility and highly differentiated network services including QoS-on-demand for an overall customer base which potentially numbers in the millions.


Here are a few links to articles, written by Alan Weissberger, which describe Clearwire’s Innovation Network and Developers program: