Jul 18, 2014 type 1 lte frame structure the basic type 1 lte frame has an overall length of 10 ms. Ltea frame structure free download as powerpoint presentation. Lte basics part i ofdma and lte frame structures youtube. The subframes may be divided into standard subframes of. Wideband decoupling between the 2 antennas for the 2. Physical layer frame structure in 4g lteltea downlink. Refer article lte physical downlink channels for more. Explain lte frame structure both for fdd and tdd techplayon. Nov 25, 2015 frame structure in lte fdd downlink frame structure in lte. One lte lb and two conjoined lte mhb mimo antennas with a. In comparison with lte for frame synchronization in nr it is necessary to. Type 1 frame structure is designed for frequency division duplex, and is valid for both half duplex, and full duplex fdd modes.
The presentations are accompanied with an audio narration. In lte the bits are stored into symbols and slots and transmitted through frames over the rf link. Number of downlink to uplink switch points within the radio frame. The biggest difference of any new wireless communication technology starts from physical layer frame structure. For the normal mode, the first symbol has a cyclic prefix of length tcp 160. Jul 27, 20 this video explains the lte technology basics, ofdma and lte frame structures and types. Manual labview communications lte application framework 2. Physical layer frame structure in 4g lte lte a downlink based on lte system toolbox sherry varghese george1, luxy mathews2, sakuntala s. Each radio frame of length 10 ms t frame 307, 200 t s comprises two halfframes, where.
Lte frame structure tdd and fdd frame structure of lte. Detailed understanding of lte physical layer involves the understanding of lte generic frame structure to support fdd and tdd. Lte uses both frequency division duplex fdd and time division. Fundamentals of network planning and optimisation 2g3g4g. The lte halfframes are further split into five subframes, each 1ms long. Ltea frame structure radio technology software defined radio. Frequency division duplexing fdd and time division duplexing tdd both paired and unpaired. Labview communications lte application framework 2. Aug 01, 2017 a tdd frame structure is shown in below figure. Jun 03, 20 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. In fdd mode, this is done using frame structure type 1.
Lte fdd uplink frame structure as in downlink, frame time and slot time in uplink is the same as in the downlink. Frame structure type 1 twenty time slots in a frame, each 0. At the initial phase of lte develoyment, you havent doubt on that every lte subframe would carries crscell sepecific reference signal in it. Frame structure type 2for 5ms switchpoint periodicity figure 22. As mentioned as per topologies, tdd and fdd there are two frame structures viz. Type 1 uses frequency division duplexing uplink and downlink separated by frequency, and tdd uses time division duplexing uplink and downlink separated in time. 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. Lte fdd systems use frame structure type 1, where radio frames are divided into subframes, times slots, and eventually symbols.
Hence lte radio frame will have duration of about 10ms. A radio frame is the largest unit of the lte frame structure, its duration is 10 milliseconds and it consists of 10 subframes each of length 1 milliseconds. It is an acronym for evolved universal mobile telecommunications system terrestrial radio access, also referred to as the 3gpp work item on the long term evolution lte also known as the evolved universal terrestrial radio access eutra in early drafts of the 3gpp. Consequently, lte, which was originally designed with fixed fdd or tdd modes with little flexibility for varying the capacity split between uplink and downlink, is being augmented with features that allow for more flexible use of radio resources. A radioframe is the largest unit of the lte frame structure, its duration is 10 milliseconds and it consists of 10 subframes each of length 1 milliseconds. As shown in the figure below, an lte tdd frame is made of total 20 slots, each of 0. 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. Although a slot is a typical unit for transmission upon which scheduling operates, nr enables transmission to. Just take a look at the overall uplink slot structure. Frame 0 and frame 5 always downlink in tdd frame 1 and frame 6 is always used as for. Key differences between the physical layers of lte and nr. That is, frame 2 not only functions as a radiator of the second antenna but also serves as a decoupling structure to attract the surface currents on the system ground plane which causes. This is the same as in lte, facilitating nr and lte coexistence.
Pillai3 1,2,3department of electronics and communication engineering, mar baselios college of engineering and technology, trivandrum, india. Physical layer frame structure in 4g lteltea downlink based on lte system toolbox sherry varghese george1, luxy mathews2, sakuntala s. In tdd there are about 7 frame configurations, based on different dlul partition. Lte frame structure based on peak to average power ratio. Fundamentals of rf sigal analyzers introduction to lte device.
Each radio frame is of duration 10ms and composed of 15 slots. The remaining six symbols have a cyclic prefix of length tcp 144. This greatly adds to deployment flexibility compared with lte, where only licensedassisted operation is supported. There are two types of frame structure in the lte standard, type 1 and type 2. The lte halfframes are further split into five sub frames, each 1ms long. The detailed radio frame structure for both frame structure types is shown in. This example shows how to create a frame containing the cellspecific reference signals cellrs in each subframe. The type of subframe, whether it is a downlink, uplink or a special subframe depends on the type of duplexing, whether fdd or tdd. Lte frame structure and resource block architecture.
Here we present information, overview, or tutorial about the lte frame and subframe structure including lte type 1 and lte type 2 frames. Downlink and uplink transmission an overview sciencedirect. Downlinkuplink ratio can vary from frame configuration 0 to 81 frame configuration 1. This video explains the lte technology basics, ofdma and lte frame structures and types. Lte a frame structure free download as powerpoint presentation. This is then divided into a total of 20 individual slots.
Frame structure type 2 is applied to a tdd duplex scheme where the downlink and. The lte application framework implements parts of a 3gpp lte release 10 compliant dl and ul phy tx and rx. Operation in unlicensed spectrum is dependent on several key principles including ultralean transmission and use of the flexible nr frame structure. 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. Structure that are used in lte where both transmitter and receiver. Even though the name still remain as ltesomething, ltenb is pretty new design from the very bottom physical layer. But anyway good thing to me was that the most important factors in uplink slot is same as the one in the downlink.
Lte tdd special subframe and its significance for cell size. Performance analysis of scfdma and ofdma in lte frame. Implementation of the physical random access channel in tdd. Downlink subframe an overview sciencedirect topics. The frame structure for the type 2 frames used on lte tdd is somewhat different. Each subframe consists of 2 slots of 14 ofdm symbols each. The figure below shows the lte frame structure under time division mode tdd type 2 and frequency division mode fdd type 1.
Figure 3 shows the frame structure for lte in fdd mode frame structure type 1. Frame structure type 2 is applied to a tdd duplex scheme where the downlink and uplink transmissions are timemultiplexed over the extent of a radio frame figure 9. Main differences in lte frame structure between the two modes are. But as we see more diverse types of subframe structure fddframe structure type1, tdd frame structure type 2, laa. The radio frame is represented in the lte toolbox product by the use of a succession of 10 cellwide settings structures with the nsubframe field set from 0 through 9 in each case. Lte subframes then consist of two slots in other words there are ten lte subframes within a frame. M p actually, there is 25% overhead in lte hence we have. Lte etsi 650 route des lucioles f06921 sophia antipolis cedex france.
A subset of the downlink subframes in a radio frame on a carrier. To keep the complexity of this application framework at a reasonably low level, only a subset of the physical layer features defined for 3gpp lte release 10 compliant devices is implemented. This is the 5thmodule in a series of lectures on 2g3g, lte, lteadvanced 4g, lteadvanced pro 4. The answer is simple, it contains the downlink channels and signals. Type 1 radio frame has a duration 10 ms and consists of equally. In order that the 3g lte system can maintain synchronisation and the system is able to manage the different types. The 10 ms frame comprises two half frames, each 5 ms long. Other than this distinction, lte tdd had little, if anything, in common with earlier timedivisionduplexing. Nr allows one common frame structure over both paired and.
Two slots make one subframe, which is 1ms long 30,720 t s. In case of dispute, the reference shall be the printing on etsi printers of the pdf version kept on a specific network drive. To start with, what does the downlink frame structure consists of. Tdd mode, based on frame structure 2, further optimizing. 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. The lte application framework is available with labview communications system design suite. Each radio frame of length 10 ms t frame 307, 200 t s comprises two halfframes, where each half frame consists of five subframes of length 1 ms. Ltenb frame structure can be summarized as follows. A frame has a duration of 10 ms and consists of 10 subframes. Eutra is the air interface of 3rd generation partnership project long term evolution lte upgrade path for mobile networks. Different frame structures are used in lte for fdd and tdd modes.
691 189 1281 469 305 585 583 165 864 660 799 1389 557 1122 1523 386 824 645 93 831 1549 1573 1048 1090 1157 398 378 244 642 1217 1476 604 748 1103 486