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EV-DO Revision B Interface
In addition to the dynamically scalable bandwidth, the hardware upgrade to Rev. B has several noteworthy technical features that translate into significant commercial advantages for operators and service benefits for customers.
  • Flexible Duplexing: A unique feature of the Rev. B implementation is that it doesnít require paired spectrum for the forward and reverse links. As a result, operators can deploy fewer reverse link carriers than forward link carriers, an ability that fits most customersí usage patterns of downloading more data than they upload. Rev. B also doesnít require the aggregated 1.25 MHz carriers to be adjacent to one another. This flexibility creates significant advantages, because it allows operators to expand existing capacity through new spectrum in different frequency bands, instead of acquiring a new block of continuous spectrum.
  • Hybrid Frequency Reuse and Multicarrier Scheduling: These features boost the download speeds of the network. Hybrid frequency reuse allows operators to improve performance by using a different frequency assignment for each sector in a cell. Rev. B applies the first frequency assignment to all three sectors in the cell, with subsequent sectors each receiving a different frequency assignment. This approach increases throughput by three to four times compared to a single Rev. A carrier, yet Rev. B uses the hardware equivalent of only two carriers. The multi-carrier scheduling scheme in the Rev. B Base Stations (BTS) maximizes cell throughput by optimizing data delivery over time and frequency. For example, with three adjacent carriers and joint scheduler the download rates improve up to 25%.
  • Load Balancing and Scheduling Efficiencies: Rev. Bís access to multiple carriers gives it the ability to assign network and spectral resources based on each serviceís requirements. These assignments are made in real-time, providing services and their users with optimal performance and capacity.
  • Consistently fast performance even in fringe coverage: One true test for any wireless technology is its ability to provide consistently high performance when users are on the fringes (edge) of a cell siteís coverage area, where signals are weak and interference may be high. Rev. B overcomes effects such as frequency-selective-dependent fading by leveraging frequency diversity: with multiple carriers serving each user, the impact of fading on a single frequency is much lower than if each user has all of his or her traffic using a single channel. The result is that Rev. Bís frequency diversity improves performance by 10%to 40%over Rev. A.