#d-scdma

Ron Gatzke: Because GSM base station is strict with requirement of the noise, it is later than WCDMA and implement zero intermediate frequency; And because TD-SCDMA adopts ascending-descending co-frequency, is not fit for direct up-conversion temporarily at present. Though zero intermediate frequency technology has already become the framework of the mainstream among the mobile phones, has just just begun to adopt among the base stations, especially in GSM base station, because it is strict with requirement of the bottom of noise, cause GSM base station to become and adopt the technical field of zero intermediate frequency at the latest, GSM system that only has zero intermediate frequency up-conversion of drib at present is trying commercially. One year ago, WCDMA base station already begun to adopt the technology of zero intermediate frequency. The technology of zero intermediate frequency can reduce the quantity of the components and parts greatly, such as save IF and RF electric-wave filter, frequency synthesizer,etc., so can make the system cost drop by a wide margin, is recognized as the development trends of base station system and mobile phone by industry. The advanced products of American letter define a manager Ron Gatzke shows: " adopt direct up-conversion (zero intermediate frequency) The intersection of GSM and the intersection of base station and until prevailing single the intersection of intermediate frequency and up-conversion system cost drop by more than 40% at present system cost of framework, and can drop by more than 60% even more than the traditional pairs of intermediate frequency up-conversion system cost. " Ron Gatzke explains, the traditional systematic advantage of pairs of intermediate frequency up-conversion is that a scheme is ripe, have numerous standard components; But the shortcoming is complicated, roomy, need 2 IF electric-wave filters and and RF electric-wave filter, in addition need frequency synthesizer. The appearance of the beginning of base station of GSM zero intermediate frequency, TD-SCDMA zero intermediate frequency wouldn't be feasible It is to utilize the component with high IP3 to obtain high performance to already begin popular systematic advantage of single intermediate frequency up-conversion at present, mixer it is out-of-band for spurious signals to lie in, compared with the situation that pair of intermediate frequency is built up it save one the intersection of IF and electric-wave filter, mixer and gain to noise temperature ratio device, the cost can save about 8-10 dollars. But the shortcoming is to need to carry on the radio frequency and filtering, needing high-performance intermediate frequency DAC to the frequency mixing product, may know the overall performance of the limit system. In addition, as to many carrier systems, it is very difficult to realize the broadband IF filter. And at this IIC exhibition, the direct up-conversion (zero intermediate frequency) that the American letter shows Framework, have simple in construction adopting high-performance the intersection of base band and DAC, electric-wave filter realize high performance projection of integrated system, need radio frequency filter namely satisfiable the intersection of Tx and requirement of template. Compared with two kinds of schemes in the above, it does not need expensive electric-wave filter (such as SAW electric-wave filter) And frequency synthesizer, users can realize the filtering function by inductance and resistance by oneself, and can reduce the gain to noise temperature ratio device quantity. So its systematic price can save 40% more than the up-conversion of single intermediate frequency. However, its shortcoming lies in that there is not processor noise and stray of an IF filter, need complicated algorithm to revise the mixer strayly. "And to engineer, the margin designed is minor, need it very carefully. " Ron Gatzke briefs on one. By the look of flexibility, zero intermediate frequency is the highest in these kinds of schemes, " our zero intermediate frequency up-conversion scheme can also be used in WiMAX system, it has already been equivalent to software radiotechnics of initial stage. " Ron Gatzke shows. But he points out, China standard TD-SCDMA can't adopt the up-conversion of zero intermediate frequency yet at present, because the upper and lower line frequencies of TD-SCDMA are the same, all different with GSM, WCDMA system. American components and parts that letter provide for direct up-conversion of GSM base station include MAX5873 (pairs of 12b DAC) ; MAX2021/2 (I/Q controller) And MAX2058/9 (RF VGA) ,The margin that can be left for engineer is 6dB. In addition, the American letter has also shown 4 carrier WCDMA zero intermediate frequency up-conversion schemes.

1.TD-SCDMA wireless network connection solution TD-SCDMA system has strong independent ability of network connection, are suitable for various such as great honeycomb, microcellular and slight honeycomb and cover the scene, the actual test of network connection has already proved, TD-SCDMA system can offer broad cover and be suitable for the high-speed mobile environment. 2.TD-SCDMA network solution Through higher spectral utilization factor and flexible to offer various the intersection of ascending-descending and symmetrical antisymmetrical ability of business their TD-SCDMA, can offer the high cost efficiency and competitive independent scheme of network connection. 3.Solution of area TD-SCDMA network connection of high telephone traffic The area of high telephone traffic includes intensive urban area and general urban area. Regional characteristic: Economy is developed, the business activity is frequent, the density of population is large, the BLDG is intensive, the wireless environment is complicated. The tactics of networking: Adopt the high-capacity macro-base station with good dilatation ability to cover Adopt different base stations that disposes according to covering provincial characteristics and traffic volume differently, flexibly High the intersection of traffic volume and area ' Such as commercial district, intensive urban area) Adopt the little base station or radio frequency to zoom out the unit appropriately ( RRU) Absorb the traffic volume, solve capacity and site selection problem The compact district of the BLDG or large-scale BLDG, adopt the little base station or base band processing unit (BBU) + the radio frequency zooms out the unit (RRU) And the indoor distribution system absorbs the business of indoor 4.The indoor covers the solution Regional characteristic: Telephone traffic is high, penetrates and losses greatly, the structure is complicated The requirement of networking: The tactics of networking: According to the office building, the characteristics of different environments such as theater, store, residential quarter, hospital, underground parking, tunnel offer the indoor with pertinence to distribute the solution Adopt the Repeater to cover as the signal source Adopt the indoor distribution system to implement covering widely Adopt the macro-base station + RRU to cover deeply BBU + RRU absorbs the traffic volume in the indoor 5.Solution of area TD-SCDMA network connection of low telephone traffic The area of low telephone traffic mainly includes the suburb county, countryside, scenic spot and highway railway. Regional characteristic: Widely coverd, the difficulty of site selection is large, traffic is low in density. The tactics of networking: Can according to different traffic volume and cover characteristic is flexible to choose the base station type and dispose the quantity of carrier of geographic zone, realize more low-cost wide area is covered Flexible to adopt the intersection of macro-base station and + RRU zoom out, go on, cover, so as to help station site choose and realize unattended operation manage 6.Solutions such as the subway, tunnel,etc. Adopt and reveal the cable and remedy the tunnel wirelessly and spread insufficiently Adopt the little base station as the signal source, set up distribution system in order to guarantee the spread of the signal along the orbit direction http://www.tdscdma-forum.org/cn/productlink/potevio.asp? l =3

3G, the full name is 3rd Generation, Chinese meaning is to point the digital communication of third generation. Imitate the mobile phone ( 1G) of the rule in first generation that came out in 1995 Can only carry on the pronunciation and converse; Digital rule mobile phones ( 2G) such as second generation appearing from 1996 to 1997 GSM, TDMA,etc. Increase the function of receive data, such as accepting the E-mail or webpage; Third generation and the first two generations' main difference are the promotion in transmitting sound and machine format speed, it can realize better the seamless is roamed in the world, and deal with picture, music, video flowing,etc. many kinds of media forms, offer including webpage browsing through, telephone conference, E-business,etc. many kinds of information service, consider and already there is good compatibility of the system of second generation at the same time. In order to offer this kind of service, the wireless network can support different data transmission speeds, that is to say in indoor, outdoor can support at least 2Mbps respectively in the environment that drive a vehicling ' Megabit /per second) , 384kbps (kilobit /per second) And the transfer rate of 144kbps. (this number value will change according to the network environment) . Relatively first generation simulation rule mobile phone (1G) And digital mobile phones (2G) such as second generation GSM, CDMA,etc. ,The name of 3G communication is various, International Telecommunications Union stipulates for " IMT-2000 " (the international cellular telephone 2000) The standard, giant of telecommunication industry of Europe are called " UMTS " Universal mobile communication system. 3G standard, International Telecommunications Union (ITU) Having confirmed global four major 3G standards altogether at present, they are WCDMA, CDMA2000, TD-SCDMA and WiMAX respectively. The major 3G standard is analyzed at present ' The picture comes from the network) China Mobile TD-SCDMA The full name is Time Division - Synchronous CDMA (synchronous CDMA of time) ,This standard is 3G standard made alone by China's Mainland, abbreviated as TD, it is the first intact mobile communication technical standard China Telecom trade over 100 years, adopt technology such as Smart antennas, jointly detecting, relay switching over, synchronous CDMA, variable spread spectrum system, adaptation power control, movement communication of the advantage that the large, spectral utilization factor high, antijamming capability of having system capacities is strong,etc.. June 29, 1999, the scientific and technical research institute of the former telecommunications of Ministry of Posts and Telecommunications in China (Datang Communication) Put forward to ITU. Standard this wait for intelligence wireless, synchronous CDMA and software radio nowadays international leading technology melts it, have unique advantage in respects such as flexibility, frequency flexibility and cost,etc. in the spectral utilization factor, to the business support. In addition,because in China bulky market, this standard pay attention to by every large main telecommunication equipment manufacturer, over half of the apparatus manufacturers in the world all announce and can support TD-SCDMA standard. This standard proposes not passing 2.5 generations' intermediate link, carry out the transition to 3G directly, is very suitable for GSM system to 3G staging. TD-SCDMA is a communication technical standard with independent intellectual property right in China, called the movement communication standard of the mainstream in 3G era with and European WCDMA, U.S.A. CDMA2000. CHINAUNICOM WCDMA The full name is Wideband CDMA, called CDMA Direct Spread too, means wide-band CDMA, this is 3G technical regulation based on that GSM network development come out, it is the broadband CDMA technology that Europe puts forward, it is essentially identical with broadband CDMA technology that Japan puts forward, further merging at present. Its backer is mainly a European manufacturer relying mainly on GSM system, Japanese company participates more or less too, including Ericsson, Alcatel, Nokia, Lucent, north electricity in America and Europe, and manufacturers such as NTT, Fujitsu, Sharp of Japan,etc.. The system can erect at Off-The-Shelf the intersection of GSM and network, can with transition more easily relatively as to system provider, and GSM system quite popular Asia expects to this set of new technical acceptance degree it will be quite high. So W-CDMA has congenital market advantages. This standard has put forward GSM(2G) -GPRS-EDGE-WCDMA(3G) Gradual progress tactics. GPRS is General Packet Radio Service (GPRS) Abbreviation,it is in EDGE Enhanced Data rate for GSM Evolution Abbreviation,it is move by communication skill not to last 2.5 generation. China Telecom CDMA2000 CDMA2000 is by the narrowband CDMA(CDMA IS95) The broadband CDMA technology which technology develops, is called CDMA Multi-Carrier too, is takes as the leading factor and proposes by U.S.A. high pass North American company, Motorola, Lucent and South Korean Samsung joined later all participate in, South Korea becomes this canonial leader now. This system came out from narrow frequently CDMAOne digital standard evolve, can be from direct staging of the original CDMAOne structure to 3G, the construction cost is cheap. Use area of CDMA have only Japan and Korea S. and North America, as more as W-CDMA backer of CDMA2000 at present. But the research and development technology of CDMA2000 is that the progress is the most quick in every standard at present, a lot of 3G mobiles have already taken the lead in emerging. This standard has been put forward from CDMA IS95(2G) -CDMA20001x-CDMA20003x(3G) Gradual progress tactics. CDMA20001x is known as 2.5 generations to move the communication skill. Main difference between CDMA20003x and CDMA20001x have lain in employing the multichannel carrier technology, through adopting three carriers to make the bandwidth improve. CHINAUNICOM is adopting this scheme to carry out the transition to 3G, and already built up CDMA IS95 network at present. Have one the intersection of 3G and standard in addition, WiMAX, come, say, should charge 4G technology on being in fact strict, but the unfinished support of obtaining International Telecommunications Union, just lower personal value by oneself, calls oneself 3G technology WiMAX The full name of WiMAX is that the microwave deposits and withdraws global intercommunication (Worldwide Interoperability for Microwave Access) ,Also called 802.16 Wireless MAN, it is another kind that offers " final mile " to enterprises and domestic consumers Broadband wireless connections scheme. Need, authorize technology this or after microwave apparatus authorized to exempt combine, because the cost is lower, will expand the wireless market of broadband, will improve the cognition degree of enterprises and the service supplier. On October 19, 2007, at the wireless communication plenary session which International Telecommunications Union holds in Geneva, voted through by most countries, WiMAX is sanctioned becoming the fourth global 3G standard following WCDMA, CDMA2000 and TD-SCDMA formally.