After the opening of the CDMA network based on IS-95A enhanced technology, China Unicom has upgraded the network to CDMA2000 1X in additional investment. At present, China Unicom has been opened in Beijing, Shanghai, Guangzhou, Chengdu, Hangzhou, Nanchang, and Haikou. It is expected that the upgrade network will start commercial operation by the end of this year, and the CDMA2000 1x technology has also become a hot spot for people.
CDMA2000 1x Development Status Currently, CDMA2000 1x should be said to be the most technological and commercialization in the third-generation mobile communication technology used by countries. It is technically, the cutting-edge research of CDMA2000 1X is the most effective, and it is also the highest throughput of wireless communication technology standard; from practical applications, along CDMaone, CDMA2000 1X, CDMA2000 3X to CDMA2000 1xEV-DV evolution, is From the base station to the core network, the market is compatible with the network, the interests of operators can get very good protection, and different mobile terminals can roam from 2G and 3G networks, and the benefits of users have also been powerful. protection. Based on the above reasons, it is not difficult to imagine that after the large-scale application of CDMA One, CDMA2000 1X will become a 3G technology with powerful competitiveness.
From IS-95, the CDMA2000 1x, which is better than IS-95, is now the basis of IS-95, and has a large reinforcement in performance. Such as 1x can support high-speed supplementary service channels, the peak rate of a single channel can reach 3.7.2kbps; with forward fast power control, the capacity of the forward channel is improved; the emission diversity mode OTD or STS can be used to improve the channel resistance Fading ability; new access method reduces the impact of interference during mobile station access, improves access success rate, and so on. The relevant test results show that the voice service capacity of the 1X system is twice the IS-95 system, while the data service capacity is 3.2 times the IS-95, and the performance improvement is considerable.
If further comparison of spectral utilization, the development prospect of 1X technology is also satisfactory. Within 1.25MHz, the 1X system can achieve data transfer of 307.2 kbps, with a spectrum efficiency of 0.3b / s / hz; 3X 5MHz to achieve a data transmission of 2Mbps in 5MHz, with a spectral efficiency of 0.4b / s / hz. This indicator is comparable to WCDMA; and CDMA2000 HDR can achieve 2.4MBPS data transmission in 1.25MHz. The spectral efficiency is greatly improved to 1.92b / s / hz; 1x Treme is 1.25MHz. Data transfer with a rate of 4.8 Mbps is achieved, with a spectral efficiency of 3.84b / s / hz. This is the fastest progress in 3G technology.
It is worth mentioning that 1X technology has fully considered the interests of operators in addition to their performance, and achieves a complete compatibility of IS-95 systems, providing a transition to third generation mobile communications A smooth choice.
Focus on the smoothing transition industry experts pointed out that since the basic technique used is always CDMA, the bandwidth occupied by a single carrier channel is always 1.25MHz, so from IS-95, CDMA2000 1X, CDMA2000 1xev to CDMA2000 3X, regardless of mobile terminals or base stations Before, backward compatibility is a true smooth transition. The compatibility of the CDMA2000 and IS-95 standard makes it easy to upgrade its base station. Taking the ZTE IS-95 base station as an example, only a single board (channel board) is replaced on the basis of the IS-95 base station, and then update some software. The base station of CDMA2000 can be upgraded.
More critical is, whether from the network system or mobile terminals, the 1x system has a standard interface compatible with 2G and 3G, and supports circuit exchange and packet exchange, with the ability to smoothly evolve to the 3G second phase. In addition, the IS-95A / B system can also evolve 3 g of the second phase of the 3G by means of 1X technology. For ordinary users, due to the compatibility of the wireless interface standard and the coincidence of the carrier frequency, the terminal of the IS-95 can roam in the CDMA2000 1x and 1xev network, and the terminal of the CDMA2000 can also be used normally in the IS-95 network, so buy terminal products The investment has also been protected. According to experts, 1X technology's wireless IP network interface uses maturity and open IETF protocols, support Simple IP and mobile IP Internet / Intranet access methods, which truly implements the mobility of Internet access. Experts say that future mobile communication networks must evolve to the full IP network direction, realize the true integration of mobile and IP, and finally form a full IP multi-business unified network, real-time voice, video, e-commerce, etc. Both will be loaded by the mobile IP.
Commercialization Progress In terms of system commercialization, the technical risk of system evolution upgrades is small due to 1X technology from commercial mature CDMaOne technology. As early as October 2000, Korea Xijing Telecom (SKT) launched the world's first commercial 1X system, with a transmission rate of up to 150kbps, exceeding the 144kbps of the 144kbps specified in IMT-2000. In April 2001, LG Telecom also launched 1X service, and some operators in Asia, Latin America and North America also said that they will launch 1X commercial services in the near future. If China's network construction is smooth, Chinese users will also taste advanced CDMA2000 1x services in 2002. As for the consumer's most concerned terminal service capability, the air channel carrying capacity of 1x system is more superior, and it has also effectively improves the system capacity, so users of 1x network will receive faster Internet access speed, even in traffic The peak phase can also browse the network at a faster rate. In addition, since 1X system is compatible with CDMaOne, 1x users can make calls in the CDMaone network without an upgrade, and CDmaOne can also make hindering in the upgraded network.
US Qualcomm recently announced that they have developed the latest Radioone 6300 mobile chip group that can operate multimode between GPRS and WCDMA, GPRS and CDMA2000. The new chipset can be run directly with the baseband processor MSM6300, so the terminal manufacturer will have the ability to utilize the MSM6300 chipset and system software to integrate the 3rd generation CDMA2000 1X and 2nd Generation GSM / GPRS service in one module. In 1x mode, the chipset supports 307 kbps data transfer, and the data transfer speed of 40 kbps can be supported in GPRS mode. This is the latest progress in the development of CDMA2000 technology and commercialization. It is clearly positive to further enhance people's confidence in 1x.
Prospect: Adjust to 1xEV forward as mentioned above, the CDMA2000 explores the most active in 3G technology in new technology. In terms of wireless interface, in order to further strengthen the competitiveness of CDMA2000 1x, 3GPP2 began to set 1X enhancement technology on the basis of CDMA2000 1x in 2000, 1xeV standard. At present, experts divide the development of 1XEV into two phases. The first phase will be based on the development of 1xEV-DO, and the second phase is the development goal with 1xEV-DV.
CDMA2000 1xEV-DO (Data Only) uses channel transmission data separated from voice. At present, HDR (High Data Rate) technology proposed by Qualcomm has become the technical standard of this phase. HDR technology with an average rate of 650 kbps, peak rate is 2.4 Mbps, and data transmission rates within 1.25 MHz bandwidth even higher than the data rate that WCDMA can provide within 5M bandwidth. It is reported that HDR has been officially adopted by 3GPP2 as the only standard of CDMA2000 1xEV-DO. The CDMA2000 1xEV-DV (Data And Voice) technology developed in the second phase of the subsequent second phase, the data channel and the voice channel will be combined for one for 4.8Mbps or even higher throughput. Various manufacturers have now proposed a variety of candidates, such as 1XTreme, LAS-CDMA, etc. At present, experts generally believe that 1xEV-Do has already have commercialization conditions, while more advanced 1xEV-DV is not mature.
