Technical aspect of cdma2000 1xEV for EVDO Wireless Broadband Service of Nepal Telecom


cdma2000 1x EDVO how it works, Technical aspect of cdma2000 1xEV for EVDO Wireless Broadband Service of Nepal TelecomThe cdma2000 1xEV (DO and DV) is the wireless data technology with channel bandwidth of 1.25MHz on FDD (duplexing) which require software and digital card upgrade on 1xRTT networks on the infrastructure side. However, this does not require new spectrum – meaning government assigned older/used frequency spectrum can be used. The requirement for new handset is important but not compulsory. New handsets will work on 1xEV at 2.4 Mbps, 1xRTT at 144 Kbps, IS-95B at 64 Kbps. Older handsets can work in 1xEV but at lower speeds.

The cdma2000 provides a seamless and evolutionary high data rate upgrade path for the current users of 2G and 2.5G CDMA technology, using a building block approach that centers on the original 2G CDMA channel bandwidth of 1.25 MHz per radio channel. Based upon the original IS-95 and IS-95A (cdmaOne) CDMA standards, as well as the 2.5G IS-95B air interface, the cdma2000 3G standard allows wireless carriers to introduce a family of new high data rate Internet access capabilities in a gradual manner within existing systems, while assuring that such upgrades maintain backward compatibility with existing cdmaOne and IS-95B subscriber equipment, according to Theodore S Rappaport. Thus, current CDMA operators may seamlessly and selectively introduce 3G capabilities at each cell without having to change out entire base stations or reallocate spectrum.

One might need to know various extensions to know the evolution of the third generation (3G) cellular network communication systems.

1xDV: 3G extension of IS-95B, shared data and voice
1xDO: 3G extension of IS-95B, data only
1xEV: 3G extension of IS-95B, data with circuit-switched voice
1xRTT: 3G extension of IS-95, one RF channel only (1xRTT stands for 1 times Radio Transmission Technology)

The cdma200 1xEV provides CDMA carriers with the option of installing radio channels with data only (cdma2000 1xEV-DO) or with both data and voice (cdma2000 1xEV-DV). The cdma2000 1xEV-DO option dedicates the radio channel strictly to data users, and supports greater than 2.4 Mbps of instantaneous high speed packet throughput per user on a particular CDMA channel. On the other side, cdma2000 1xEV-DV supports both voice and data users, and can offer usuable data rates upto 144 kbps with about twice as many voice channels as IS-95B.

The cdma2000 1x supports an instantaneous data rate of up to 307 Kbps for a user in packet mode, and yields typical throughput rates of up to 144 Kbps per user, depending on the number of users, the velocity of a user, and the propagation conditions. cdma2000 1x can also support up to twice as many voice users as the 2G CDMA standard, and provides the subscriber unit with up to twice the standby time for longer lasting battery life.

The IMT-2000 standards defines the cellular air interface for cdma2000.

Air interface: cdma2000 US TIA TR45.5
Mode of Operation: Multi-carrier and Direct Spreading DS-CDMA a N = 1.2288 Mcps (Megachips per second) with N = 1, 3, 6, 9, 12
Duplexing Method: FDD and TDD modes
Key features:

  • Backward compatibility with IS-95A and IS-95B.
  • Downlink can be implemented using Multi-Carrier or Direct Spreading.
  • Uplink can support a simultaneous combination of Multi-carrier or Direct-Spreading.
  • Auxiliary carriers to help with downlink channel estimation in forward link beam forming.

The good point with 3G cdma2000 technology is that the standard has been developed for both Frequency Duplexing (FDD for Mobile Radio) and Time Duplexing (TDD for in-building cordless) applications.

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