posted by: Paul DeBeasi
In May, Sprint and Clearwire formed a $14.5B joint venture that will focus entirely on WiMAX. The joint venture will be called Clearwire and includes investment from Google, Intel, Comcast, Time Warner, and Bright House Networks. According to joint venture announcement, the new Clearwire expects to dramatically enhance the speed with which customers access the Internet. What does it mean to “dramatically enhance the performance of Internet access”?
First, we must define what we mean by the term performance. Performance includes many factors. Two of the most visible metrics, from a user’s point of view, are download speed in megabits per second (Mbps), and upload speed in Mbps. Download speed has traditionally been the metric that most users care about because it affects the user’s web-browsing experience. However, the emergence of peer-to-peer networking and the growing need to upload user-generated content such as videos and pictures is creating the need for faster upload speeds.
Next, we must draw a distinction between peak performance and average performance. Peak performance is the best possible performance that the technology can achieve under idealized conditions. The peak performance makes for a great headline, but users will never experience this lofty performance level. Conversely, average performance is the performance that users will typically experience using a deployed mobile service. Average performance can vary throughout a coverage area and is affected by many factors such as channel bandwidth, backhaul capacity, path loss, shadowing, network load, antenna configuration, and mobility speed.
According to Intel, the average per-sector download speed of WiMAX is approximately 30 Mbps using a 20 MHz channel (similar to IEEE 802.11g average throughput). This means that there is approximately 30 Mbps of shared bandwidth available for download transmission per sector. For example, if there are 20 users connected to the network using the same sector, and if half of the users are downloading data at the same time, then each user will receive approximately 3 Mbps average download throughput. Note that WiMAX has sophisticated quality of service mechanisms that will help network operators equitably regulate per-user performance.
Over time, average performance will improve as the WiMAX network evolves. In addition, other technologies such as High Speed Packet Access (HSPA), Evolution-Data Optimized (EV-DO), and Long Term Evolution (LTE) will compete with mobile WIMAX to offer high speed Internet access.
Clearwire promises to dramatically enhance the speed of Internet access with their new mobile WiMAX service. Although many factors can affect performance, the service is expected to provide average download speeds of several mega-bits per second. Other technologies such as HSPA, EV-DO, and LTE will also compete with Mobile WiMAX.
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