CDMA2000 1xEV-DO Overview
CDMA2000 1xEV-DO (1x Evolution Data Optimized) is a third-generation (3G) wide-area wireless technology that delivers high-speed mobile data services. Wireless service providers on a global basis are adopting EV-DO and are revolutionizing mobile broadband connectivity for millions of subscribers. Delivering peak data speeds above 2 Mbps and an average data throughput of 300-600 Kbps, EV-DO networks support a wide range of innovative mobile broadband information, communication and entertainment applications. EV-DO is part of the CDMA2000 family of ITU-approved, IMT-2000 (3G) standards developed to enable high quality wireless voice and data services. CDMA2000 technologies have been deployed by over 257 operators worldwide and serve over 438 million subscribers. (Source: CDMA Development Group, 2008)
CDMA2000 1xEV-DO Rev A
CDMA2000 1xEV-DO Rev A, the latest commercial generation of EV-DO technology, increases the peak data transmission download speed to 3.1 Mbps, the peak upload speed to 1.8 Mbps and enables telephony-based services such as voice, push-to-talk and video telephony over a wireless IP network.
EV-DO Rev-0 maximizes user data rates and optimizes network capacity utilization through sophisticated rate adaptation, macro-diversity and multiplexing schemes. Unlike other technologies that provide a constant fixed data rate, an EV-DO system constantly monitors channel conditions and adapts the data rate upward as conditions improve. EV-DO uses a packet-based Time Division Multiplexing (TDM) scheme that ensures traffic is efficiently multiplexed over the forward link, and sector capacity is dynamically allocated in a matter of milliseconds. Optimizing the allocation of resources – particularly during peak traffic periods – improves the overall throughput for each active subscriber. In addition, EV-DO technology employs a powerful error-correction scheme, which optimizes network performance.
CDMA2000 1xEV-DO Overview
- CDMA2000 3G Standard
- 1.25 MHz Licensed Spectrum
- 5-15 Km typical cell radius
- Fully mobile, no line-of-sight required
- Seamless integration with cdmaOne and CDMA2000 1X networks
- Easy overlay for TDMA and GSM environments
- EV-DO Rev 0 – data only
- EV-DO Rev A – voice and data
- Peak rate
- EV-DO Rev 0 – 2.4 Mbps
- EV-DO Rev A – 3.1 Mbps
EV-DO Rev A support voices services because it provides a fast reverse link (uplink) and end-to-end Quality-of-Service (QoS). QoS in 1xEV-DO Rev A is based on flows. A flow is defined by several parameters including its sensitivity to delay, data rate changes and acceptable packet error rate. The VoIP application, for instance, would use a delay sensitive flow for its bearer traffic. This delay-sensitive flow would get priority over a best-effort flow used for email or music download. The Video Telephony application would not only use a delay sensitive flow for voice but would also use a rate sensitive flow for the video stream to maintain interactivity.
Evolution of CDMA2000 Networks
With 1xEV-DO Rev-A, the focus of CDMA2000 standards development has firmly shifted from advancing circuit switched technologies such as 1xRTT to advancing the packet switched technology, EV-DO.
Beyond 1xEV-DO Rev-A, the next step in the development of CDMA2000 standards is the scalable aggregation of multiple 1.25MHz 1xEV-DO Rev A carriers. Called NxEV-DO (or Rev B), this technology enables operators to aggregate multiple 1xEV-DO carriers and deliver higher bandwidth and peak data rates. (For example: If N=3: 3 x 3.1Mbps peak rate per 1.25MHz carrier = 9.3 Mbps peak rate). NxEV-DO not only allows CDMA2000 operators to effectively compete against technologies such as UMTS that operate in a 5 MHz wide band but also supports the delivery of new, high-bandwidth multimedia applications. EV-DO technology provides a cost-effective foundation for the development of an advanced IP-based broadband wireless voice and data network. Serving a broad base of consumer and business customers, EV-DO networks will continue to evolve and set the pace for innovative wireless voice, data and multimedia services.