EV-DO Release 0 was commercially launched in 2002 as the world’s first mass-market mobile broadband technology. EV-DO has since quickly become the most widely deployed wireless broadband standard in the world. As of Q3 2009, the EV-DO networks of 105 operators served 147 million subscribers in 46 countries worldwide.
The success of EV-DO Release 0 led to the development of EV-DO Revision A (Rev. A) and Revision B (Rev. B). These standards include innovative features for providing ubiquitous broadband coverage over a wide area. Figure 1 shows the evolution path of CDMA EV-DO technology family. Rev. A has been commercially deployed since 2006, while Rev. B will be deployed in the near future. This article describes the enhancements included in Rev. A and Rev. B that enable fast and efficient broadband wireless access in WAN deployments.
Figure 1. Evolution Path of CDMA EV-DO Technology
Downlink, uplink, VoIP and more
Rev. A introduces a number of significant changes to improve airlink performance of EV-DO.
•Peak rates of 3.1 Mbps on the downlink and 1.8 Mbps on the uplink
•Sector capacity of 1.5 Mbps downlink and 1.2 Mbps uplink
•Enhanced QoS capabilities, improving the connection setup time and lowering end-to-end delays
•VoIP capacity of up to 49 calls per sector
Major features such as QoS provide greater flexibility for supporting a whole new class of applications that were not previously possible on wireless networks. Some of the key applications enabled include VoIP, push to talk/push to media, video telephony and low-latency gaming.
Rev. B provides benefits to both service providers and users. By bundling multiple Rev. A carriers together, service providers can offer more capacity for most widely consumed bursty traffic such as web browsing. Rev. B also improves the performance of all Rev. A data applications, and provides an enhanced user experience across the entire coverage area.
Key benefits of Rev. B
With the proliferation of smart mobile devices, service providers need to introduce additional DO carriers to meet the growing data demand. With a simple software upgrade, operators can combine multiple DO carriers to offer Rev. B. Service providers can now leverage the trunking efficiency of multiple carriers to offer over 50% higher capacity for typical bursty applications such as HTTP, clip downloading, etc.
A key advantage available with Rev. B is the ability to selectively upgrade areas of the network that need higher capacity or greater performance. Because of the backward compatibility and seamless roaming across Rev. A networks, Rev. B can be gracefully rolled-out across a network. Users in those areas will immediately experience improved performance, while continuing to benefit from the availability of Rev. A across the wider coverage area.
Figure 3 shows a possible deployment scenario. Operators may choose to deploy three carriers in dense urban areas to provide greater capacity, two carriers in suburban areas, and one carrier in rural areas to provide continuity of coverage across the entire region.
Figure 3. Possible Deployment Scenario
With selective multi-carrier upgrade, additional carriers in the hotspots can provide higher capacity due to reduced interference from neighbor cells. Users also benefit from the spatial interference reduction in these hotspots, which leads to superior user experience. Figure 4 shows the improvements in data rates in such hotspots due to spatial interference reduction.
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Figure 4. Improved Data Rates of Multicarrier Deployment in Hotspots
The Internet user experience is noticeably improved in Rev. B. Pictures, videos, and audio files can now be uploaded or downloaded much faster. Web surfing is significantly faster as RF carriers are added. HTTP page response times decrease by 38% with a two-carrier Rev. B deployment, and up to 50% with three carriers.
The enhanced data rates of Rev. B allow operators to offer it as the primary broadband connection in under-served markets, while QoS ensures the high revenue services such as VoIP are concurrently supported. In addition, applications such as video surveillance and video conferencing can now be offered to a larger number of users.
Rev. B allows operators to leverage their Rev. A network equipment by adding Rev. B functionality to existing channel cards through a software upgrade. Multilink RLP and multi-carrier operation can be added, allowing aggregation of carriers for Rev. B devices. With the software upgrade option, up to three Rev. A carriers can be aggregated to provide 9.3 Mbps of peak throughput in 5 MHz. Backward compatibility and seamless roaming across Rev. A, Release 0, and even 1xRTT data networks, ensures that Rev. B devices are able to work with existing networks across the world. In addition, Rev. B network support for existing devices allows consumers to benefit from greater economies of scale.
A hardware upgrade of the channel cards to Rev. B enables even higher FL peak rate and spectrum efficiency. Rev. B introduces new physical layer rates by adding 64-QAM. This increases the single carrier Rev. B physical layer peak rate to 4.9 Mbps. In a typical 3 carrier deployment, Rev. B will support a peak rate of 14.7 Mbps. Rev. B also provides more packet formats for finer data rates and achieves higher spectral efficiency per carrier.
The bottom line
DO Rev. A enhancements improve the uplink performance of EV-DO and allow low-latency applications such as VoIP and low-delay gaming. DO Rev. B allows higher data rates by aggregating Rev. A carriers, and improves the user experience for all applications available over Rev. A. Rev. B also provides tremendous capacity benefits to operators by bundling already deployed Rev. A carriers. A software upgrade to Rev. B provides a cost-effective way to achieve high data rates while leveraging the installed base of EV-DO users.