EVDO

EVDO (ev-do) is actually three word abbreviation: DataOnly similarities (Evolution),. Their entire called: DO CDMA20001xEV - CDMA20001x evolution, is the path (3G) a stage. This path has two stages of development, the first phase IS called 1xEV - DO, namely "DataOnly", it can make operators use a and IS - 95 or the same bandwidth CDMA2000 can achieve as much as CDMA carrier frequency before Mbps to the 2.4 data transfer rate, currently has been the ITU accepted as international 3G standard itu-t IS already have commercial applications, and conditions. The second phase is called 1xEV - DV. 1xEV - DV meaning "DataandVoice", it can be done in a CDMA carrier frequency voice and data at the same time support.

introduction

Ev-do is English traded or Data similarities - abbreviation of similarities - Data campaigns. Sometimes also write EVDO or EV do.

Ev-do (CDMA2000 1x ev-do standard) introduction

1xEV - CDMA2000 DO is a kind of can meet mobile high-speed data business technology. A ev-do channel bandwidth 1.25 MHz.

The actual need when using two different arrangement of carrier support voice and data services, though this reduced the frequency spectrum efficiency utilization ratio, but from CDMA2000 1X on see, the 1xEV - CDMA2000 DO + data transfer ability has been greatly exceed WCDMA (currently WCDMA can realize R4 version air interface rate of 2.4 Mbps / 5Mhz, and 1xEV - CDMA2000 DO Release 0 rate 1xEV CDMA2000 2.4 Mbps, DO new lesson today for A rate - 1xEV - CDMA2000 Mbps, 3.1 DO new lesson today B rate for Mbps). 930m And judging from technology to achieve it, voice business and data services, maintain separate high quality speech, got higher data transfer rate. The network planning and optimization CDMA2000 1X and CDMA2000 1xEV on same, each DO - the main equipment manufacturers CDMA2000 system can support CDMA2000 1X from 1xEV - to DO smooth, this to telecom operators upgrade in technology and investment options are very ideal, help 1xEV - CDMA2000 DO promotion.

Development situation

DO CDMA20001xEV - Qualcomm originated from the standard of technical, early in the HDR when Qualcomm in 1997 to put forward the CDG HDR (high speed data), then the concept of through continuously improve and experiment in 2000 to march to the name CDMA20001xEV - DO 3GPP2 submitted a formal technical plan. 1xEV mean & # 39; & # 39; & # 39; & # 39; Similarities & # 39; & # 39; & # 39; & # 39; And also said standard of development, the meaning of DataOnly (DO for a later in order to have a better express the meaning of this technology, DataOptimized DataOnly instead, says ev-do technology is CDMA20001X network to provide data business in a significant enhancement method). In the same year 3GPP2 vote in October for the standard definition in the United States 0024, c.s. TIA/EIA called IS - 856. In December 2001 at the meeting, CDMA20001xEV itu-t DO CDMA2000 technology as a family - a branch of IMT by absorbing for one of the 2000 standards.

The development of standards and technical means of realization of the most quickly to support the technology is applied to the market, because ev-do technology is actually comes from the HDR technology, Qualcomm company Qualcomm company also can therefore launched timely corresponding MODEM chip in the second quarter, 2001 Qualcomm company has announced that can batch production ev-do network side and terminal CSM5500 and the chip with MSM5500. Actually technical standards and the competition is actually chip in order to get the market leadership, known as Qualcomm companies rely on CDMA technology patents and chip manufacturing capacity were generous profits. For CDMA technology patent income, other companies, but for natural cannot lay the profit is already CDMA chips many powerful chip maker and communications equipment manufacturer has long coveted the, the world already has samsung, Texas instruments, nokia and other companies have the ability to fabricate CDMA2000 series of MODEM chip, in fact, samsung from 1999 in its base station has used in the manufacturing CDMA20001X chip, in its ev-do base station is still use their development ev-do chip. "We welcome the competition, but not willing to lose market share," which is Qualcomm's view, some like now of table tennis, but from a long-term perspective, competitive appear is indeed outweigh the costs.

From the system equipment manufacturers look, so far, has announced its support for ev-do device manufacturers are:

Hitachi, Lucent, on LGIC, Nortel, Ericsson, Motorola, ComDev Airvana, such as huawei and zte,. And the original CDMA20001X equipment manufacturers are almost all the equipment can claim "smooth upgrade to ev-do". Indeed, South Korea KTFreetel SKT and is the samsung bs, took a small price 1X upgrade to 1X + from ev-do. Now the network operation is good. Here we can tell me a little bit about the EV - DV. In CDMA20001X stage from technology itself, after speaking should say EV - DV subsequent evolutionary stages is 1X, EV - DV or compatible CDMA20001X. So someone has ever want to skip directly to DO, in the previous stage, the DV communication exhibition had company had EV - demo." But EV - DV is to get voice and data services in the same carrier, and is more inside transmission of data services, and therefore high speed from technology to achieve itself and actual network there are great difficulty, still have a lot of problems to be experiment, simulation to analyze and solve. From the foundation and the key chip manufacturing perspective, manufacturing ev-do chip CDMA20001X chip need to have experience in manufacturing, so far only Qualcomm and samsung have their own CDMA20001X chip, and Qualcomm is always a strong pitch from their HDR's ev-do, South Korea and Japan have also provided by samsung ev-do stations in networking, so although in commercial 3GPP2 identified in May last year CDMA20001xEV - DV standards, but distance the actual business equipment appeared also needs a very long period of time.