Physical layer frame structure in 4g lteltea downlink based. Lte frame structure tdd and fdd frame structure of lte. But as we see more diverse types of subframe structure fddframe structure type1, tdd frame structure type 2, laa. 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.
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. Implementation of the physical random access channel in tdd. The answer is simple, it contains the downlink channels and signals. Lte uses both frequency division duplex fdd and time division.
Performance analysis of scfdma and ofdma in lte frame. The presentations are accompanied with an audio narration. 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. Number of downlink to uplink switch points within the radio frame. Each radio frame is of duration 10ms and composed of 15 slots. Each radio frame of length 10 ms t frame 307, 200 t s comprises two halfframes, where. Apr 18, 2018 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. Labview communications lte application framework 2. Detailed understanding of lte physical layer involves the understanding of lte generic frame structure to support fdd and tdd. This is then divided into a total of 20 individual slots. To start with, what does the downlink frame structure consists of.
This is the same as in lte, facilitating nr and lte coexistence. Downlinkuplink ratio can vary from frame configuration 0 to 81 frame configuration 1. The lte application framework is available with labview communications system design suite. Lte basics part i ofdma and lte frame structures youtube. Frame structure type 2 is applied to a tdd duplex scheme where the downlink and. Lte frame structure and resource block architecture. Lte etsi 650 route des lucioles f06921 sophia antipolis cedex france. Physical layer frame structure in 4g lte lte a downlink based on lte system toolbox sherry varghese george1, luxy mathews2, sakuntala s. 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. Lte frame structure based on peak to average power ratio. 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. Main differences in lte frame structure between the two modes are. Even though the name still remain as ltesomething, ltenb is pretty new design from the very bottom physical layer.
Downlink and uplink transmission an overview sciencedirect. Lte fdd uplink frame structure as in downlink, frame time and slot time in uplink is the same as in the downlink. In order that the 3g lte system can maintain synchronisation and the system is able to manage the different types. This greatly adds to deployment flexibility compared with lte, where only licensedassisted operation is supported. Here we present information, overview, or tutorial about the lte frame and subframe structure including lte type 1 and lte type 2 frames. Operation in unlicensed spectrum is dependent on several key principles including ultralean transmission and use of the flexible nr frame structure. Ltenb frame structure can be summarized as follows.
Frame structure type 1 twenty time slots in a frame, each 0. This is the 5thmodule in a series of lectures on 2g3g, lte, lteadvanced 4g, lteadvanced pro 4. Downlink subframe an overview sciencedirect topics. Just take a look at the overall uplink slot structure.
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. Fundamentals of rf sigal analyzers introduction to lte device. The type of subframe, whether it is a downlink, uplink or a special subframe depends on the type of duplexing, whether fdd or tdd. M p actually, there is 25% overhead in lte hence we have. 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.
Lte downlink frame structure long term evolution 4g. The lte halfframes are further split into five sub frames, each 1ms long. Although a slot is a typical unit for transmission upon which scheduling operates, nr enables transmission to. But anyway good thing to me was that the most important factors in uplink slot is same as the one in the downlink.
Other than this distinction, lte tdd had little, if anything, in common with earlier timedivisionduplexing. 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. The 10 ms frame comprises two half frames, each 5 ms long. In fdd mode, this is done using frame structure type 1. Eutra is the air interface of 3rd generation partnership project long term evolution lte upgrade path for mobile networks. Refer article lte physical downlink channels for more. Nr allows one common frame structure over both paired and.
Lte fdd systems use frame structure type 1, where radio frames are divided into subframes, times slots, and eventually symbols. Lte a frame structure free download as powerpoint presentation. The figure below shows the lte frame structure under time division mode tdd type 2 and frequency division mode fdd type 1. In comparison with lte for frame synchronization in nr it is necessary to. As shown in the figure below, an lte tdd frame is made of total 20 slots, each of 0. Aug 01, 2017 a tdd frame structure is shown in below figure. Two slots make one subframe, which is 1ms long 30,720 t s. There are two types of frame structure in the lte standard, type 1 and type 2. The frame structure for the type 2 frames used on lte tdd is somewhat different.
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. As mentioned as per topologies, tdd and fdd there are two frame structures viz. Different frame structures are used in lte for fdd and tdd modes. 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. Type 1 uses frequency division duplexing uplink and downlink separated by frequency, and tdd uses time division duplexing uplink and downlink separated in time. In tdd there are about 7 frame configurations, based on different dlul partition. Release 8 and release 9 architecture, access technique and frame structure, physical layer lte advanced. Frame structure type 2for 5ms switchpoint periodicity figure 22. 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. Manual labview communications lte application framework 2. Pillai3 1,2,3department of electronics and communication engineering, mar baselios college of engineering and technology, trivandrum, india.
This example shows how to create a frame containing the cellspecific reference signals cellrs in each subframe. Structure that are used in lte where both transmitter and receiver. Nov 25, 2015 frame structure in lte fdd downlink frame structure in lte. Hence lte radio frame will have duration of about 10ms.
Key differences between the physical layers of lte and nr. The lte halfframes are further split into five subframes, each 1ms long. Jul 18, 2014 type 1 lte frame structure the basic type 1 lte frame has an overall length of 10 ms. A subset of the downlink subframes in a radio frame on a carrier. Ltea frame structure radio technology software defined radio. This is the 5thmodule in a series of lectures on 2g3g, lte, lte advanced 4g, lte advanced pro 4. Type 1 frame structure is designed for frequency division duplex, and is valid for both half duplex, and full duplex fdd modes.
Frequency division duplexing fdd and time division duplexing tdd both paired and unpaired. Type 1 radio frame has a duration 10 ms and consists of equally. Figure 3 shows the frame structure for lte in fdd mode frame structure type 1. Two types of radio frame structures are designed for lte. 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. Type 1 lte frame structure the basic type 1 lte frame has an overall length of 10 ms. Each subframe consists of 2 slots of 14 ofdm symbols each. Jul 27, 20 this video explains the lte technology basics, ofdma and lte frame structures and types. Lte tdd special subframe and its significance for cell. In the time domain, lte transmissions are organized into frames of length 10 ms, each of which is. Introduction to lte raj jain washington university in saint louis saint louis, mo 63.
At the initial phase of lte develoyment, you havent doubt on that every lte subframe would carries crscell sepecific reference signal in it. For the normal mode, the first symbol has a cyclic prefix of length tcp 160. 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. Lte subframes then consist of two slots in other words there are ten lte subframes within a frame. Frame 0 and frame 5 always downlink in tdd frame 1 and frame 6 is always used as for. 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. The biggest difference of any new wireless communication technology starts from physical layer frame structure. The remaining six symbols have a cyclic prefix of length tcp 144. Explain lte frame structure both for fdd and tdd techplayon. Tdd mode, based on frame structure 2, further optimizing.
A frame has a duration of 10 ms and consists of 10 subframes. Wideband decoupling between the 2 antennas for the 2. The detailed radio frame structure for both frame structure types is shown in. Fundamentals of network planning and optimisation 2g3g4g. One lte lb and two conjoined lte mhb mimo antennas with a.
This video explains the lte technology basics, ofdma and lte frame structures and types. Lte tdd special subframe and its significance for cell size. In case of dispute, the reference shall be the printing on etsi printers of the pdf version kept on a specific network drive. Physical layer frame structure in 4g lteltea downlink. Ltea frame structure free download as powerpoint presentation. The lte application framework implements parts of a 3gpp lte release 10 compliant dl and ul phy tx and rx. Physical layer frame structure in 4g lteltea downlink based on lte system toolbox sherry varghese george1, luxy mathews2, sakuntala s. In lte the bits are stored into symbols and slots and transmitted through frames over the rf link.
555 927 481 1531 593 1485 998 1255 1295 1215 1434 1212 1556 213 1399 73 1245 1121 1369 158 494 181 712 356 926 354 1161 495 1074 464 450 1254 423 483 241 805 124 314 436 419 975 527 445 1357