Lteadvanced is not a new technology, instead it is an evolution step in the continuing development of lte. Aug 01, 2017 long term evolution lte supports both fdd and tdd duplex mode. Jul 30, 2016 this video has been re uploaded with human voice for better understanding. Lte uses several different types of logical, transport and. Fdd and tdd duplexing the lte toolbox product can generate and manipulate signals for the duplexing arrangements specified in the lte standard.
Lte subframes then consist of two slots in other words there are ten lte subframes within a frame. Acknack multiple acknowledgements and negative acknowledgements are combined on the uplink control channels. Jun 03, 20 this article will explain the downlink frame structure. The answer is simple, it contains the downlink channels and signals. Different frame structures are used in lte for fdd and tdd modes. The subframes may be divided into standard subframes of. Lte frame structure and resource block architecture reference signal structure division mode enodeb ul channel and dl channel time domain signal structure physical resource division mode and frequency for lte resource block architecture. This is then divided into a total of 20 individual slots. Includes special subframes for switching downlinktouplink. Parameters frame structures phy resources modulation, channel coding, and physical channels. Figure 3 shows the frame structure for lte in fdd mode frame structure type. But as we see more diverse types of subframe structure fdd frame structure type1, tdd frame structure type 2, laa frame structure type 3, i see my confidence gets weaker.
Design and implementation of spatial interweave ltetdd. At the initial phase of lte develoyment, you havent doubt on that every lte subframe would carries crscell sepecific reference signal in it. Myung 2 beyond 3g international mobile telecommunications imt2000 introduced global standard for 3g. While focus had been mostly on fdd, tdd gains importance. This video has been re uploaded with human voice for better understanding. In communication systems, a user needs to exchange data with one or more parties through a shared resource a common channel. Lte a frame structure free download as powerpoint presentation. Long term evolution lte supports both fdd and tdd duplex mode.
Ltea frame structure free download as powerpoint presentation. Analysis of ltetdd inchannel interference lication note mobile operators are embracing lte technology and are aggressively deploying it using two techniques. One example of this is the subframe structure that has been adopted within lte tdd tdlte. Wo20162785a1 flexible special subframe configuration. But as we see more diverse types of subframe structure fddframe structure type1, tdd frame structure type 2, laa. Variable duplex technology within bands as well as. The 5g nr frame structure depicts subframes,slot and symbol configurations.
Lte fdd, tdd, tdlte duplex schemes electronics notes. Tdd has a special subframe type, which is a transition period from downlink to uplink. Outline lte introduction lte phy standard descriptions protocol architecture standard docs. Lte frame structure tdd and fdd frame structure of lte. Dynamic tdd for lte a and 5g september 2015 volker pauli, yi li, eiko seidel nomor research gmbh, munich, germany abstract in recent years, mobile communication traffic has continuously been shifting from being dominated by voicecall traffic with symmetric uplink downlink capacity requirements to burstlike. Mobile class targets 100 mbps with high mobility and nomadic local area class targets 1 gbpswith low. Jul 18, 2014 type 1 lte frame structure the basic type 1 lte frame has an overall length of 10 ms. The ltetdd standard uses time domain duplexing for scheduling uplink ul and downlink dl transmissions, where both the ul. Implementation complexity for fdd is much less compared to that of tdd, because of the frame structure and also radio design. One example of this is the subframe structure that has been adopted within lte tdd td lte. Expected in the 2008 time frame, lte is a 3gpp standard that provides for an uplink speed of up to 50 megabits per second mbps and a downlink speed of up. Of the two versions of lte, the frequency division duplex, fdd version is more widely used than the time division, tdd version also known as td lte. Overview long term evolution lte is the next step forward in cellular 3g services. Dimensioning of lte network description of models and tool, coverage and capacity estimation of 3gpp long term evolution radio interface abdul basit, syed masters thesis submitted in partial fulfillment of the requirements for the degree of masters of science in technology espoo, february, 2009.
The figure below shows the lte frame structure under time division mode tdd type 2 and frequency division. Ltea frame structure radio technology software defined radio. As lte fdd is full duplex system, means both the downlink and uplink transmission happens at the same time at different frequencies. Nr uses flexible subcarrier spacing derived from basic 15 khz subcarrier spacing used in lte.
Type1 shared by both full and halfduplex fdd type2 applicable to tdd a radio frame has a length of 10 ms and contains 20 slots slot. In lte, each downlink subframe and the dwpts in the case of tdd. In order that the 3g lte system can maintain synchronisation and the system is able to manage the different types. In tdd, the transmission is divided into time domain, means at one moment of time either downlink subframe is. In eutra frame structure, each downlink subframe and the dwpts fields in the case of tdd is divided into a control region, consisting of the first ofdm symbols of the subframe, and a data region, comprising the remaining ofdm symbols of the subframe. Celladvisor analysis of ltetdd inchannel interference. Two slots make one subframe, which is 1ms long 30,720 t s.
The lte frame structure for the fdd and tdd schemes was discussed in chapter 9. The remaining six symbols have a cyclic prefix of length tcp 144. It describes 5g frame as per nr new radio 3gpp standard. Lte tdd special subframe and its significance for cell size. For the normal mode, the first symbol has a cyclic prefix of length tcp 160. Downlink subframe an overview sciencedirect topics. The frame structures for lte differ between the time division duplex, tdd and the frequency division duplex, fdd modes as there are different requirements on segregating the transmitted data. Difference between lte fdd and tdd long term evolution 4g.
The 10 ms frame comprises two half frames, each 5 ms long. Figure 3 shows the frame structure for lte in fdd mode frame structure type 1. Lte physical layer lte tdd frame structure type 2 one radio frame 10 ms 2 halfframes 10 subframw subframes 0 and 5 always for dl special subframe with various partitioning of following fields dwpts dl gp guard period uppts ul, always followed by an ul subframe supports 7 different uldl configurations. Dynamic tdd for ltea and 5g september 2015 volker pauli, yi li, eiko seidel. In lte, downlink and uplink transmissions are organized into radio frames of duration 10ms consisting of 10 consecutive subframes, each consisting of a number of consecutive ofdm symbols, as shown in. In this page, i will describe on nr frame structure that is specified in 3gpp specification 38. Lte frame structure and resource block architecture. The answer is simple, it contains the downlink channels. Lte frame structure lte frame and subframe structure. The ltetdd standard uses time domain duplexing for scheduling uplink ul and downlink dl transmissions, where both the ul and dl signals occupy the same frequency band and are separated in time rather than frequency. As mentioned as per topologies, tdd and fdd there are two frame structures viz. Here we present information, overview, or tutorial about the lte frame and subframe structure including lte type 1 and lte type 2 frames.
In tdd there are about 7 frame configurations, based on different dlul partition. The lte halfframes are further split into five subframes, each 1ms long. The transmission timeline for the downlink and uplink may be partitioned into units of radio frames, and each radio frame may be partitioned into 10 subframes with indices of 0 through 9. The lte half frames are further split into five subframes, each 1ms long. In fdd mode, this is done using frame structure type 1. Frame structure type 1 twenty time slots in a frame, each 0. This article will explain the downlink frame structure. The major difference in tdd and fdd is that in tdd system a single frequency is shared in time domain between uplink and downlink where as in fdd separate frequencies are used for uplink and downlink transmission. Depending on whether the data is transmittedreceived simultaneously, the fol. Type1 frame ahmed hamza long term evolution lte a tutorial october, 2009 22 48. Lte basics part i ofdma and lte frame structures youtube. The slots, subframes and frames have the same duration as before. Lte advanced is not a new technology, instead it is an evolution step in the continuing development of lte.
Downlinkuplink ratio can vary from frame configuration 0 to 81 frame configuration 1. There has been long long discussions on frame structure both in academia and in 3gpp and now we have pretty clear agreements on what a nr5g radio frame would look like. The downlink and uplink frame structure parameters are the same, except that the timedomain underlying symbols in the downlink are ofdm symbols, whereas in the uplink the underlying symbols are scfdma symbols due to the use of different multiple access methods in. There are two types of frame structure in the lte standard, type 1 and type 2. It enables very low latency, fast harq acknowledgements, dynamic tdd, coexistence with lte and transmissions of variable length for example, short duration for urllc and long duration for embb. Of the two versions of lte, the frequency division duplex, fdd version is more widely used than the time division, tdd version also known as tdlte. Lte frame and subframe structure information, overview, or tutorial about the lte frame and subframe structure including lte type 1 and lte type 2 frames.
It was initially specified as part of release 10 of the 3gpp. This has been such a great way for me to earn extra money. Uplinkdownlink timefrequency structure for fdd and tdd 2. During the early development stages of lte, lte tdd had two frame structure options, including one frame structure that was very similar to the frame structure used by tdscdma or lcr tdd, as it is referred to in the 3gpp specifications. Lte tdd special subframe and its significance for cell. Lte downlink frame structure long term evolution 4g. Jul 27, 20 this video explains the lte technology basics, ofdma and lte frame structures and types. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. To start with, what does the downlink frame structure consists of. Type 1 lte frame structure the basic type 1 lte frame has an overall length of 10 ms. Explain lte frame structure both for fdd and tdd techplayon. Type 1 uses frequency division duplexing uplink and downlink separated by frequency, and tdd uses time division duplexing uplink and downlink separated in time. The frame structure below figure 1 is applicable to tdd.
Frame structure a special sub frame that allows switching between downlink and uplink transmission. The frame structure for the type 2 frames used on lte tdd is somewhat different. Tdd mode, based on frame structure 2, further optimizing. The frame structure follows a time and frequency grid similar to that of lte, with a higher number of configurable parameters. Nr frame structure supports tdd and fdd transmissions and operation in both licensed and unlicensed spectrum. Lte, the long term evolution systems is the major milestone in stepping towards 4g evolution. This video explains the lte technology basics, ofdma and lte frame structures and types. In release 15, at most, there will be 3300 subcarriers, for a maximum bandwidth of 400 mhz. For the beginners, there is always a confusion about the frame structure, the physical channels etc, so to make their job easy, i am writing this article. Key differences between the physical layers of lte and nr. Systems beyond imt2000 imtadvanced is set to introduce evolutionary path beyond 3g. There has been long long discussions on frame structure both in academia. An important feature in lte is its adoption of radio resource management rrm procedures which. Overview of the 3gpp long term evolution physical layer.
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