Data Transmission Rates & WiMAX Service Rates

Data transmission rate refers to the amount of digital information that is transferred over a transmission medium over a specific period of time and is commonly measured in the amount of bits that are transferred per second (e.g. bps, Mbps).

The data transmission rate for WiMAX systems varies based on factors including radio channel bandwidth (1.25 MHz to 28 MHz), modulation type (BPSK, QPSK, QAM) and channel coding type (percentage of bits dedicated to control and error protection). The raw data transmission rate of a WiMAX radio channel can be in excess of 155 Mbps using QAM modulation. The allocated data transmission rates to each user are typically 1 to 3 Mbps allowing WiMAX operators to have several hundred subscribers for each RF channel.

WiMAX Service Rates

A rate plan is the structure of service fees that a user will pay for services. Rate plans are usually divided into monthly and usage fees.

In the early 2000s, wide area wireless systems (e.g. mobile telephone systems) were limited to relatively low data transmission rates (regularly below 20 kbps). Users were often required to pay for bandwidth on a time or usage basis. Consequently, the cost of this data transmission was approximately 10 cents per kilobyte ($100 per megabyte).

The ability of WiMAX systems to provide high data transmission rates with a limited amount of equipment allows for a substantial reduction in operation cost which thereby leads to significant lowering of service rates. The service rate cost for WiMAX systems in 2006 was approximately 2 to 3 cents per megabyte (99.97% lower than mobile data rates in the mid-1990s).

Figure 1 shows a sample wireless broadband service rate plan for a specific WiMAX system in 2006. This example shows that users may select from 3 rate plan options; basic, standard or premium. Each rate plan has a maximum downlink and uplink data transfer rate associated with it along with a monthly service fee. The amount of allocated data that can be transferred as part of the rate plan (at no cost) may be limited (e.g. 100 MByte maximum) or it may be unlimited (e.g. premium plan). If the user exceeds the allocated data transfer amount for their selected rate plan, they are charged a usage fee (e.g. 2 to 3 cents per MByte). In addition to the service fees, WiMAX service providers may charge a connection fee (setup fee) and there may be a leasing charge for equipment that is provided by the WiMAX service provider (e.g. WiMAX modem).

Figure 1: Sample Wireless Broadband Service Rate Plan 2006

WiMAX Compared to Mobile Telephone Data Systems

Mobile telephone systems are fully automatic wide-area high-capacity RF networks made up of a group of coverage sites called cells. As a subscriber passes from cell to cell, a series of handoffs ensures smooth call continuity.

Mobile telephone systems have evolved to offer a mix of voice and packet data services. These systems are composed of interlinked cells that have the capability to transfer connections from tower to tower. The radio channel bandwidth is relatively narrow compared to WiMAX systems and the modulation types are less efficient (i.e. more robust). Therefore, the maximum data rates of mobile telephone data systems are lower than that of WiMAX.

Figure 1 shows how WiMAX is positioned to fit with cellular data and Wi-Fi systems. WiMAX systems are designed to provide centrally managed highspeed data services over wide areas, whereas Wi-Fi systems are designed to provide self-managed wireless data services over relatively small geographic areas.

Figure 1: Comparison between WiMAX and 3G

Finally, mobile telephone data services are designed to provide a mix of voice and medium speed data services to customers as they move throughout a mobile system.

WiMAX Compared to 802.11 Wi-Fi

802.11 Wi-Fi is an industry standard developed by the IEEE for wireless network communication to provide wireless local area network (WLAN) services. It usually operates in the 2.4 GHz or 5.8 GHz spectrum and permits data transmission speeds from 1 Mbps to 54 Mbps.

WiMAX differs from Wi-Fi in various ways including service range, data transmission throughput, quality of service capability and security processes.

Outlined in Figure 1, 802.16 WiMAX and 802.11 Wi-Fi systems are designed to provide different capabilities. WiMAX systems are well suited for wide area networks that are managed by a service provider and Wi-Fi systems are a good choice for local area networks.

Figure 1: Differences between WiMAX and Wi-Fi