EVDO (ev-do)

EVDO (ev-do) is actually the abbreviation of three words: similarities (Evolution), Data campaigns. Their entire called: 1xEV - DO, is CDMA2000 CDMA2000 1x evolution (3G) a path that a stage. This path has two stages, with the first stage being called 1xEV - DO, namely "Data campaigns", it can make operator by using a distinction - 95 or with the same frequency width CDMA2000 software-processable can realize CDMA Mbps of up to 24,000 prior to Data transfer rate, at present has been the ITU ITU accepted as international 3G standards, and already has commercial applications conditions. The second phase is called 1xEV - DV. 1xEV - DV meaning "Data and Voice", it can be done in a CDMA software-processable on support both Voice and Data.

CDMA2000 1xEV - DO technical analysis

1xEV - DO is an optimized for packet data service, high frequency spectrum efficiency CDMA wireless communication technology, can be in 1.25 MHz bandwidth inside offer peak rate of 2.4 Mbps high-speed data transmission service. This rate above even WCDMA 5MHz bandwidth inside can provide the data rate. In order to does not affect the existing network under the premise of voice communications support high-speed data business, 1xEV - DO adopted will voice channel and the method of separation of data channel. This is because the data and voice has different characteristics. If time delay, data rate on the realtime requirements below voice business; Ber, data service to bit error probability of the requirements of higher phonetic business, Former reverse asymmetric, generally speaking, prior to data service (base station to the mobile station) is higher than the rate of reverse several times demand. And voice traffic is strict symmetric business.

1xEV - DO with existing IS - 95 and CDMA2000 1x network compatible, thus very good protection of distinction - 95 and CDMA2000 1x operator's existing investment. Among them, 1xEV - DO code piece rate, power demand, channel bandwidth and IS - 95 and CDMA2000 1X identical; 1xEV - DO can continue to existing network planning and rf components, base station with distinction - 95 or CDMA2000 1x syncretic, low cost. DO 1xEV - power control with soft switch and the way IS - 95 and CDMA2000 1x different, its core thought IS through the dynamic control data rate rather than power, so that each user to the highest rate may get communication. Prior to link using variable time buttress way time multiplex. In 1xEV - DO in total, access to the highest power to send, make position of the user to get very high rate. Prior to channel, DO 1xEV - using the virtual soft handoff mechanism, the mobile station at the same time receive only from the same access points of data. According to the real-time dynamic rate control (DRC) information, base station can be quickly mutual switching. Meanwhile, base station measurement load dry than (C/I) and in DRC channel to the mobile station instructions best access points, The mobile station constantly measuring pilot.finally intensity, and constantly requires a current with channel condition accord with the data rate. Access points at the current mobile station can support the maximum rate coded. When the user needs to change and channel conditions change, dynamically determined optimization data rates. In reverse, 1xEV - DO with distinction - 95, 1X CDMA2000 same soft handoff technology, the mobile station by multiple access point send information receiving; Also, support high-speed packet data sudden. 1xEV - DO adopt Turbo coding technology, reverse with continuous pilot tones. Make demodulation performance improved. In addition, 1xEV - DO adopt CDMA2000 enhanced wireless link protocol (RLP), with TCP protocol common reduce frame error rate. Its powerful air link jian right and encryption algorithm guarantee the safety of users.

CDMA2000 1x ev-do proposed background

In the late 1990s, along with the wireless access to the Internet, the growth of demand for wireless packet data service requirements will grow. Wireless LAN, as a representative of the wireless access technology, while can provide higher bandwidth, but in safety, billing and cover and so on the limitation of, have limited their extensive application. Cellular mobile telecommunication network can provide a broad range of coverage, has the good billing system and security architecture, if combined with the new high-speed wireless technology, provides wireless Internet business in will have good prospects of application. Meanwhile considering with ADSL, as a representative of the data cable network competition needs, requirement for this new cellular network can at least provide compared with ADSL fitting data bandwidth. In view of this, qualcomm company since 1996 developed HDR (High Data Rate) technology, and in 2000 was TIA/EIA IS accepted for Release 0-856 standard (version), also called Packet Data Rate HRPD (High) or 1x ev-do. 1x says it with CDMA2000 1x system used by the rf bandwidth and yards piece rate exactly the same, have good backwards compatibility, EV (similarities says it is CDMA2000 1x Evolution version, Data DO (top) says it is specifically targeted at packet Data service and optimizes the technology. 1x ev-do in 2001 by itu-t R accept for 3G technology standard one.

CDMA2000 1x ev-do design thought

1x ev-do system initially is aimed at non-real-time, asymmetric high-speed packet data service and design. High-speed transmission is to 1x ev-do system design of core function requirement, high-speed meant based on limited bandwidth resources, using cellular network to provide mobile users, similar to the wired network (e.g., ADSL) that the high-speed data business. The original design 1x ev-do system, main is to provide web browsing, wireless Internet download documents such as business, they will either have a real-time feature, and the business's QoS guarantee no strict requirements; Either with asymmetric feature requests to link before the transfer rate and throughput is obviously higher than reverse links. Obviously, along with the service development, to 1x ev-do system function requirements will further improve. In CDMA2000 1x system, low-speed data service and voice business is code division multiplexing, sharing base station transmission power, spread spectrum code and frequency resource. Base power control technology by quickly closed loop to compensate for the impact of channel decline, so as to achieve higher spectrum efficiency, to in low-speed data and voice business terms, it is the best choice. But, for high-speed packet data business, this rapid power control does not guarantee system has high spectrum efficiency, especially when high-speed packet data service with the traditional voice business is used yards points Shared frequency and power stations way, the efficiency of the system will resources is low.

1x ev-do system of basic design thought is will high-speed packet data service and low voice and data services separated, using single carrier provide high-speed packet data service, while the traditional voice business and low-speed packet data service by CDMA2000 1x system to provide, so can obtain higher spectrum efficiency, network design is more flexible. In the specific design, should give full consideration to 1x ev-do system and CDMA2000 1x compatibility, and use CDMA20001x / 1x ev-do two-mode Terminal or mixed terminals (Hybrid Access Terminal) interoperable, will realize low voice business with high speed and packet data service common services.

CDMA2000 1x ev-do development situation

From 1996 qualcomm company started developing a HDR technology, 2000 formation 1x ev-do standard, 2002 1x ev-do products into the commercial stage, the globe in early 2005, world has established more than ten 1x ev-do commercial network and its steps to the market was accelerated. Below respectively from standardization progress, commercial progress and the market prospect 3 aspects to illustrate 1x ev-do development situation.

Standardization progress

1x ev-do the Internet as wireless outspread, first IS to provide asymmetric high-speed packet data service and design, so far, 1x ev-do air interface standards have developed Release 0 and Release A two versions, the corresponding TIA/EIA standards are respectively IS - 856-0 and IS - 856 - A.

IS - 856-0 in October 2000 release, it supports prior to single user peak rate for 2.4576 Mbit/s, reverse single user peak rate of 153.6 kbit/s, suitable to provide based on file download, surfing the web and E-mail etc of nonsymmetric packet data service. In order to support section real-time multimedia services, qualcomm in 2003 the company in IS - 856-0 on the basis of enhancement, increased the receiving diversity, QoS guarantee, radio and equalization, and other functions, and the terminal and system of baseband processor chips are introduced, the upgrade of zero frequency technology. But these enhancements not a standard format publication.

Along with the development of multimedia data business, all sorts of new business form appear ceaselessly, bandwidth and QoS guarantee of system requirements also enhances unceasingly. Since there are backward link bandwidth and QoS assurance limitations, 1x ev-do Release0 system to meet the relevant requirements of business development. In March 2004, 3GPP2 released 1x ev-do Release A version, and was TIA/EIA accepted as IS - 856 - A. IS - 856 - A support single user reverse peak rate of 1.8 Mbit/s, prior to peak rate further improve to 3.1 Mbit/s. IS - 856 - A adopted A multi-user grouping and smaller packet encapsulation, provide real-time business need quick access, rapid paging and low latency, transmission characteristics, in order to meet different requirements of different QoS business, Introduces multiple antenna launch diversity technology, effectively improve the high-speed packet data in bad wireless environment the reliability of the transmission problem. As 1x ev-do air interface standards of development, its A interface, terminal technical specifications and new business norms also worked out in succession, and continuous development.

Commercial progress

Since May 2002 SKT opened the world's first commercial network 1x ev-do since 1x ev-do maintained a rapid development momentum, by January 2005, existing SKT, KTF, KDDI, Verizon, 13 Monet Vesper, operators success deployed 1x ev-do commercial network and has hundreds of 1x ev-do terminal and ten balance ShangWangKa into the commercial, global 1x ev-do subscribers has more than 12 million.

At present, most 1x ev-do commercial systems and terminal are based on Release version 1.0, A few equipment manufacturer also are being developed or has been able to provide enhanced based on Release 0 1x ev-do equipment, 1x ev-do Release A system products is expected to enter the business at the end of 2005, end products are expected to enter the business in 2006.

Market prospect

The key to success of 3G services, mainly lies in the wireless data business whether can thorough popular feeling, information provided to the user service can generate tremendous appeal. Japan, South Korea and the United States operators is through high quality music clips and high-definition movie clips downloads colorful content service, allows data business flow, greatly improves a substantial increase ARPU values.

On the one hand, 3G service request network has high data throughput, to provide high speed data services, 1x ev-do the technical characteristics of the guarantee it. 1x ev-do can support CDMA2000 1x provide all the packet data business, for rate and QoS requirements strict business, 1x ev-do can provide better service and the user experience. For example, for wireless data access operations, 1x ev-do access service level has been close to popular cable ADSL, For wireless data value-added services, 1x ev-do can provide higher quality of streaming media services and faster audio&video large files downloaded service.

On the other hand, 3G service need operators, system manufacturer, terminal manufacturer and content providers, and between the close cooperation in a relatively short period of time to solve problems on its industry chain. First, operators and system factories mutual cooperation and resolve in a short time network coverage and the stability of the system, operators for problems such as mobile streaming media coverage business provides a good network, which can support services, Secondly, terminal operators and manufacturers joint efforts, supply much money can support mobile streaming media business such as mobile phone, Finally, operators and content providers joint effort, in content, for mobile streaming media business such as the characteristic, combining the use of user habits and hobbies, common development and rapid updating mobile streaming media business such as the content.

At present, 1x ev-do in multiple country achieved successful business application, and verifies the 1x ev-do the Internet as wireless outspread, provide high-speed packet data service in its excellent performances, also indicates 1x ev-do wide prospect of market.