Prepaid phone cards, cheap calling cards online

Our online shop offers you phone cards for long distance calls. You can find the best rate to the international call and save many money. Buy only cheapest phone cards online in our shop.

Main Page Telecom News Enter Your Account / Register Buy Phone Card Best Rates FAQ and Help
International calls
call from
call to

ZTE fine-tuning CDMA for VoIP


ZTE said today it has successfully performed a VoIP call over the a CDMA 1X EV-DO Revision B network, demonstrating the viability of dedicating an entire CDMA network to 3G while still supporting both voice and data. ZTE said its Rev. B solution will be available for commercial deployment in the third quarter.

Rev. B is a 3GPP2 standard that stacks EV-DO Rev. A channels on top of one another, creating a wide high-capacity channel for bandwidth-hungry applications. Rev. B doesn’t improve upon the overall capacity of the individual channels, so technically the total capacity of the overall network does not increase. But by combining multiple 1.25 MHz carriers into a single large carrier, the average transaction time for every user decreases—files are downloaded faster, a Web page loads more quickly—allowing the network to move onto the next user and next transaction more quickly. The phenomenon, explained by queuing theory, allows the network to perform more transactions at a faster pace over a single broad channel than it could over several narrower ones, leading to a higher capacities available to each individual user, if not in the network overall. ZTE said its trials achieved over 9.3 megabits per second on the downlink and 5.3 Mb/s on the uplink over 3 bundled carriers.

Despite its advantages, Rev. B has received a rather lukewarm reception from CDMA operators, though it technically requires only a software upgrade at the base station to implement. One of the main reasons is that all EV-DO channels are by definition data channels and cannot carry circuit-switched voice. For every 1.25 MHz channel used to create a stacked Rev. B channel, a 1X voice channel must be taken out of commission.

ZTE proposes, however, that circuit-switched voice capacity can be replaced with VoIP as Rev. B will have both the capacity and low latency to support high-volumes of VoIP traffic. Eventually the majority of CDMA 1X network could be replaced with Rev. B. While ZTE is focusing on bundling three 1.25 MHz in its initial Rev. B platform, as many as 15 carriers could be stacked in the future supporting downlink rates as high as 73.5 Mb/s.

In order to fully take advantage of Rev. B’s gains, though, operators would have to introduce Rev. B handsets and mobile devices into their networks, which may ultimately explain their reluctance to deploy Rev. B. Many of the major CDMA operators worldwide have already committed to deploying Long Term Evolution (LTE) networks, and, in the case of Verizon Wireless, those networks will start popping up this year. LTE will not only give CDMA operators the same wide channels as Rev. B—allowing them to take advantage of the queuing theory principles—but it is also a more efficient technology that crams more bits into a hertz of spectrum. With those sorts of capital investments -- and the associated introduction of new 4G devices -- on the horizon, CDMA operators are likely to bypass Rev. B entirely, and focus their broadband efforts on LTE.


Related News

IPv6 Forum lauds worldwide VoIP interoperability
The IPv6 Forum and some of its members today announced the successful completion of VoIP calls using IP version 6 (IPv6), demonstrating worldwide interoperability among VoIP technologies. IPv6 is the next generation of Internet technology, designed by the Internet...
Tiny Genband swallows Nortel’s giant VoIP business
After not qualifying offer down, Genband has won's Nortel VoIP wealth to mask a bid for $282 million. The plan, which is likely to close in the second quarter, do one of the VoIP equipment provider Genband the world's largest operator, combined with their wealth...
Dittberner reports Q3 growth spurt for VoIP
The summer season reaped quite a harvest for vendors of equipment for voice over IP as analyst firm Dittberner Associates reported this week what it called an impressive 67.8% worldwide market increase over last quarter.In the firm’s Worldwide Q3 2005 NGN Shipments...
VoIP market holds breath as deadline passes
The FCC-imposed deadline for filing Enhanced 911 compliance reports by voice-over-IP service providers came and went yesterday with little fanfare. The fanfare will come when the FCC tallies the reports and makes its decisions on enforcement of the potentially...
Calling Cards © 2008