IEEE 802.20, also known as the Mobile Broadband Wireless Access (MBWA) standard, was developed by the IEEE to provide high-speed, efficient wireless communication systems designed for mobile users. Its primary goal was to offer seamless broadband access with high data rates, low latency, and high mobility support, making it suitable for vehicular and nomadic users.
Key Objectives
IEEE 802.20 aimed to fill a niche in the wireless communication landscape by delivering broadband wireless access optimized for mobile environments, with the following core objectives:
- High-speed mobility: It was designed to support users moving at speeds up to 250 km/h, making it ideal for use in cars and trains.
- Efficient use of spectrum: The standard emphasized spectral efficiency, enabling operators to offer more data to users with a given bandwidth.
- Support for diverse environments: It targeted both urban and rural settings, providing coverage in densely populated areas as well as in wide-area rural deployments.
- Low latency and high throughput: Aimed at supporting applications requiring low-latency connections (e.g., real-time video streaming, gaming), with data rates projected to exceed those of contemporary 3G systems.
- All-IP network architecture: The network structure was designed to support an end-to-end IP (Internet Protocol) architecture, facilitating integration with internet services and applications.
Technical Features
- Frequency Range: 802.20 was designed to operate in licensed frequency bands below 3.5 GHz. This range was selected to ensure better signal propagation characteristics and compatibility with existing mobile networks.
- Data Rates: It targeted peak data rates of 1 Mbps to 4 Mbps for mobile users, depending on the environment and mobility conditions.
- Mobility: One of the defining features was its ability to maintain connectivity even when users were moving at high speeds (e.g., in a car or on a train), supporting handovers between cells without significant service interruption.
- Channel Bandwidths: The standard allowed for flexible channel bandwidth configurations, typically ranging from 1.25 MHz to 20 MHz, ensuring it could adapt to various spectrum availability and operator requirements.
- Air Interface: The air interface was optimized for IP traffic, with support for technologies like adaptive modulation and coding (AMC) and orthogonal frequency-division multiplexing (OFDM) or time-division multiple access (TDMA) to ensure robust and efficient communication in varying radio environments.
- Spectral Efficiency: IEEE 802.20 aimed for high spectral efficiency, targeting 1 to 2 bits/Hz/s per cell in the downlink (DL) and slightly lower in the uplink (UL).
Development and Challenges
- Standardization Process: The IEEE 802.20 working group was formed in 2002, and early efforts focused on developing a standard for mobile broadband wireless access optimized for vehicular mobility.
- Competition and Overlap: The development of IEEE 802.20 faced challenges due to overlapping objectives with other standards, notably WiMAX (IEEE 802.16e) and 3GPP’s efforts with LTE. The competition between these standards, combined with industry politics and shifting market demands, led to delays and complications in the finalization of the 802.20 standard.
- Controversies: The 802.20 working group experienced controversies related to corporate influence and allegations of bias in the standardization process, which resulted in a temporary suspension of the working group in 2006. The group was later restructured and resumed work, but by this time, competing technologies like LTE had gained significant momentum. Despite this, the development of IEEE 802.20 contributed valuable insights to the design of mobile broadband systems, particularly in terms of mobility management, spectral efficiency, and support for high-speed vehicular use.