Umtstdd, an acronym for universal mobile telecommunications system umts timedivision duplexing tdd, is a 3gpp standardized version of umts networks that use utra tdd. Fdd and tdd, which are technically very similar and part of the same radio access specification. Lte fdd and lte tdd are virtually identical with the exception of a. Difference between fdd lte networks and tdd lte networks. Lte is a high speed wireless technology from 3gpp standard. Lte physical layer fundamentals and test requirements. Umts is an umbrella term for the third generation radio technologies developed within 3gpp. Tdd design for umts longterm evolution ieee conference. The tdd mode is optimized for public micro and pico cells and unlicensed cordless applications. Umts to gsm or umts to gprs umts supports a variety of user data rates and both packet and circuit switched services system composed of three main subsystems telcom 2720 4 umts system architecture ue user equipment that interfaces with the user. Common tdd fdd standard and design ensures economy of scale. Objectives edit tdscdma was developed in the peoples republic of china by the chinese academy of telecommunications technology catt, datang telecom, and siemens ag in an attempt to avoid dependence on western technology. Lte is an ideal technology to support high date rates for the services such as voice over ip voip, streaming multimedia, videoconferencing or even a highspeed cellular modem.
Lte fdd and tdd were both defined and introduced as part of the 3gpp specification in 2009 to make efficient use of paired and unpaired spectrum allocations over a common, core network architecture. Requirements for support of assisted galileo and additional navigation satellite systems aganss frequency division duplex fdd ts 25. Lte 3gpp long term evolution seems to be the next generation in mobile phone technology as many providers are beginning to augment their networks with lte. Key benefits streams on multiple transmitters to multiple receivers. Utra tdd is a utra that uses timedivision duplexing for duplexing. Frequency division duplex fdd requires two separate communications. Cheat sheets are useful when debugging an issue or testing a test cases and you just need a quick look instead of going into the specification. Where lte tdd favored by a majority of implementations because of flexibility in choosing uplink to. Lte supports both frequency division duplex fdd and time division duplex tdd modes to provide.
Lte1060 tdd fdd handover duplex telecommunications. Tdscdma umtstdd lcr networks are incompatible with wcdma umts fdd and tdcdma umtstdd hcr networks. Wcdma for umts principles u introduction u cdma background history ucode division multiple access cdma u why cdma. Umts terrestrial radio access the most significant change in rel. A compact carrier generation system enabling proper interoperability among quadband gsm, wcdma fdd and tdd, and wlan 802. The umts frequency bands are radio frequencies used by third generation 3g wireless universal mobile telecommunications system networks. Fdd lte and tdd lte are two different standards of lte 4g technology. This page covers advantages and disadvantages of tdd and fdd.
Longterm evolution lte will provide substantial enhancements to umts 3g systems including improved system capacity and coverage, low latency, reduced operating costs, multiantenna support, flexible bandwidth operations and seamless integration with existing systems. Fdd also works on a cable where transmit and receive channels are given different parts of the cable spectrum, as in cable tv systems. Cept report 39 report from cept to the european commission in. This document applies to umts and lte handsets and related terminal equipment. Umts mimo, fdd and tdd improve throughput and access efficiency. The universal mobile telecommunications system umts is a third generation mobile cellular. L t e t e c h n o l o g y i n t r o d u c t i o n c. There is a very high degree of commonality in the technical specifications ts between the fdd and tdd modes of lte. Also, the spectral efficiency which is a function of how well a given spectrum is used by certain access technology of fdd is greater than tdd. The voice solution and voice capacity in lte are also illustrated. One known as fdd or frequency division duplex uses two channels, one for transmit and the other for receiver. The wcdma tdd system is well suited for indoor areas and wide area data systems. It mentions tdd advantages, tdd disadvantages, fdd advantages and fdd disadvantages. Tdd uses a single frequency band for both transmit and receive.
The transmissions tofrom the base station uplinkdownlink are the technical terms for each direction occur at the same time. The anquectel ec20 multimode lte module ec20 series is the new generation of quectels lte modules. Wcdma time division duplex wcdma tdd definition and diagram. Select one channel bandwidth per band for trp and trs tests for lte fdd and tdd. Power and range fdd systems transmit data over half the bandwidth, for twice as long as tdd systems 2x5 mhz fdd system transmits data over 5 mhz bandwidth for the entire frame 10 mhz tdd system transmits data over a 10 mhz bandwidth for about half of the frame if both systems transmit at 200mw, power is more. Lte supports both frequency division duplex fdd and time division duplex tdd modes to provide deployment. Utran supports time tdd and frequency division duplex fdd. This gives the fd frequency division of fdd frequency division duplex. Laboratory tests on the coexistence between 4g tdd and 3g4g fdd in the 19001920 mhz spectrum band. This tutorial section on wcdma umts basics covers following sub topics.
Umts long term evolution lte technology introduction. Tdd tdd handovers, through interfrequency changes and tdd fdd handovers, handovers to 3g wcdma and hpsa systems, and finally to handing over from tdd to gsm. Wcdma for umts principles introduction cdma background history key parameters code division multiple access cdma why cdma. Ltetdd and ltefdd also operate on different frequency bands, with ltetdd. During tdd operation, the mobile device receives a burst of data, waits until its assigned time slot, and transmits a burst of data on the same frequency.
While the specified rf environment for both lte fdd and tdlte requires multiple inputmultiple output mimo operation, test and validation methods remain to be determined. The voltagecontrolled oscillator vco exhibits a phase noise of 118 and 125. Lte physical layer fundamentals and test requirements fanny mlinarsky octoscope. Tdd stands for time division duplex and fdd stands for frequency division duplex. Finally, the main differences between lte tdd and fdd modes are examined and hspa evolution in 3gpp releases 7 and 8 is described.
Tdd allowed by the fcc, cept, japan, canada and many other countries. When using a tdd system, there are a number of characteristics that are pertinent for tdd systems. Laboratory tests on the coexistence between 4g tdd and 3g4g. Lte for umts is one of the first books to provide a comprehensive guide to the standards and technologies of lte. Block edge mask contributes to tdd fdd coexistence. With the higher level of integration between the two modes, the effort required to support them should be less than it was in the past. Fdd and tdd modes for lte has resulted in only one rf specification document each for the ue and the enb. Division multiple access technology and frequency division duplexing fdd the term wcdma also refers to one of the itus imt2000 standards, a type of 3g cellular network.
In this document we have recorded all the rrc measurements and the meaning of those events. Umtstdd is a mobile standard built upon the umts 3g standard, using a tdcdma, tdscdma, or other 3gppapproved, air interface that uses time division duppg lexing tdd. Again, filters are used to keep the channels separate. The wcdma tdd system uses the same cdma channel coding process as the wcdma fdd system. Another scheme known as tdd, time division duplex uses one frequency, but allocates different time slots for transmission and reception.
Requirements for support of assisted global positioning system agps. With tdd, transmission to the base station from you phone, and from the base station to your phone occur on the same frequency. Fdd tdd system comment 1 midband 1920 1980 mhz 2110 2170 mhz fdd. The ratio between uploads and downloads on a ltetdd network can be changed dynamically, depending on whether more data needs to be sent or received. As we know, mobile phone traffic is divided into two parts. While ltefdd uses paired frequencies to upload and download data, ltetdd uses a single frequency, alternating between uploading and downloading data through time.
Low noise amplifier for lte band 5 introduction of lte application application note an457 6 revision 1. Umts to gsm or umts to gprs umts supports a variety of user data rates and both packet and circuit switched services system composed of three main subsystems telcom 2720 4 umts system architecture. Difference between fdd lte fdlte and tdd lte tdlte. User equipment ue radio transmission and reception tdd 3gpp ts 25. While a full implementation of umts, it is mainly used to provide internet access in circumstances similar to those where wimax might be used. Tdd can be used with paired and unpaired spectrum tdd can use either subband and the middle guard band from an itur recommendation. Wcdma tdd physical layer vs wcdma fdd physical layer utra. The radio access specifications provide for frequency division duplex fdd and time division duplex tdd variants, and several chip rates are provided for in the tdd option, allowing utra technology to operate in a wide range of bands and coexist with other radio access technologies.
Utra fdd 2 and utra tdd 3 systems compliant with the etsi en 301. Cdma principles spreading codes multipath radio channel and rake receiver problems to solve macro diversity and soft handover nearfar problem and power control umts general requirements fdd vs. There are two modes of operation for lte technology. Umts tutorial umts channels measurements phy layer tdd vs fdd phy rrc states security cell search bands uarfcn frame the page covers difference between wcdma tdd physical layer vs wcdma fdd physical layer as per utra physical layer specifications. Lte uses both time division duplex tdd and frequency division duplex fdd mode.
1032 187 389 1327 727 750 1047 78 107 1396 790 650 1646 925 1494 892 732 1271 1317 716 679 124 1198 316 1638 1454 262 668 106 299 637 1042 1440 1240 1045 246