Two duplex schemes FDD and TDD are supported. International Search Report for PCT/CN2008/001840 dated Jan. Downlink Uplink Frame TIME. IWSON / VTC2015 Summary In LTE-TDD, the amount. HI all,Please go through video of LTE Frame Structure (FDD and TDD). Conformance Test Setup. 1 TDD—Time-Division DuplexFIG. LTE TDD frame structure is shown below. One slot made up of 7 small blocks called 'symbol'. Myung 17 Frame Structure • Two radio frame structures defined. LTE Frame structure. 5 GHz range use a common 5G NR frame structure. Each Operator can select the Frame Structure (1 out of 7 options), defining the UL/DL ratio. FDD is operated in the paired spectrum (see Sect. 7µs. 6. from below figure you can see for μ = 0 (highlighted row) Number of OFDM symbols in one slot = 14. TD-LTE has a 10 ms TDD frame structure. Frame Structure Type 2: TDD. A method performed by a wireless device for determining a timing advance (TA) offset in a new radio (NR) network is described herein along with associated network devices and systems. Whereas further optimizations can be made for Frequency Division Duplexing (FDD) systems, the combination of sTTI and Time Division Duplexing (TDD) has limits. Switching Points . Uplink and downlink configurations are used to create subframes (0 to 6). As shown 5 ms periodicity frame have two “S” sub frame and 10 ms framesTD-SCDMA frame structure is shown in figure 2, which depicts frame hierarchy. About the frame structure, the previous it scattered mentioned some, such as the blog "LTE-TDD Random Access Process (2)-Preamble Code preamble format and time-frequency location", in the preamble format, referring to the length of each sub-frame is 30720Ts, and different up and down sub-frame configuration , downlink, special sub. Radio frames for downlink and uplink transmission are 10ms long. Downlink Uplink Frame. NB-IoT-U introduces frame structure Type 3N. The WiMAX frame adopts a subframe ratio structure of 29:18, the LTE TDD frame adopts a subframe ratio structure of subframe configuration 1, and an UpPTS time slot and a last uplink symbol of a last uplink subframe which are in the LTE TDD frame. Under the existing LTE TDD frame structure , which subframe can be UL or DL is fixed within a radio frame . We will go through Mobile WiMAX OFDMA physical layer which. May 6, 2021 On-Demand Demo See a Celona 5G LAN in action and learn the basics Get Access This episode of Field Journal we’ll go deep into the TDD-LTE frame structure in the CBRS spectrum band, and touch on. The frame 402 has two 5 ms half frames 404, and each of the half frames 404 includes five 1 ms subframes 406. Download scientific diagram | LTE Uplink TDD Frame Structure from publication: Efficient Device-to-Device (D2D) Offloading Mechanism in LTE Networks | With the increase in mobile traffic and the. Figure 9. 3. LTE is mainly designed for high speed data applications both in the uplink and downlink. UL and DL time slots, Downlink Pilot Timeslot (DwPTS) – downlink part of special subframe, Uplink Pilot Timeslot (UpPTS) – uplink part of special subframe, Guard Period (GP) The Special Subframe in LTE-TDD (DwPTS, GP, UpPTS)The main objective of the presented field measurement campaign was to confirm that the laboratory measurement results of LTE local network systems using 2. In frame structure Type 1, each 10 ms radio frame is divided into 10 equally sized subframes. LTE is designed primarily for full duplex operation in paired spectrum. TBS Index Advanced LTE TDD Carrier–DownlinkLTE-Advanced Physical Layer Overview. Flexible Bandwidth: 1. It enables very low latency, fast HARQ acknowledgments, dynamic TDD, coexistence with LTE and transmissions of variable length (for example, short duration for URLLC and long duration for enhanced MBB (eMBB)). cyclic prefix). A phone must typically perform the following tasks (Figure 5): Acquire a signal on a given LTE carrier frequency. All. The invention discloses a method (500) for a cellular communications system (100), in which traffic is sent in frames (200), each frame comprising a first number of subframes (201-210), with a second number of said subframes being available for at least either uplink or downlink traffic. 1. . Hence there are total 20 slots in a radio frame. OFDM with a cyclic prefix is the basic modulation scheme selected to combat severe frequency-selective multipath fading. 0, and 1. Using the latency model shown in Figure 11. Frame Structure • Two radio frame structures defined. The remaining six symbols have a cyclic prefix of length TCP = 144 ⋅ Ts ≈ 4. Type 1: Used in LTE FDD Type 2: Used in LTE TDD The following text shows the frame structure of each type. An operator can choose a specific TDD configuration depending on the service requirements; Frame always starts with a Downlink subframe, used for advertising the frame descriptor information i. • The equipment requires to be switched between transmission and reception. All networks operating within the 3. TDD. Figure 2. · Sub-frame size= 1 ms. It is a TDD type of frame structure which is a natural choice since ETSI band 54 and FCC band 902–928 MHz are both unpaired bands. So, it is very important to understand the slot structure and other details about slot-based scheduling etc. Type 1: Used in LTE FDD. LTE-TDD and NR-TDD CBSDs, GAA channelization and SAS-CBSD protocol extensions. Each subframe has two slots. 2. Increasing frame configuration; Configuration: 3GPP release: Downlink to uplink switch point. There are seven possible configurations for LTE TDD frame as shown below. UMTS TDD. MCCH modification period, repetition period radio frame offset, subframe allocation;. B. As shown in Figure 1, the total length of downlink pilot time slot (DwPTS), GP, and uplink pilot time slot (UpPTS) fields is equal to 1 ms duration. These parameters are defined in 38. Subframes 0 and 5 contain synchronization signal and broadcast information necessary for a UE to perform synchronization and obtain relevant system information. It consists of a 10 ms radio frame divided into 20 slots, numbered 0 to 19, each with a duration of 0. It is defined as 1/(15000 x 2048) seconds (=0. 2–1) Symbol level TDDResource Block of RACH in LTE Frame Structure : Preamble length is 6RB , 1 RB=180KHZ, so 6RB=1. 11 and Rel. In Extended CP, number of symbols within a slot is decreased. 2. Now the question comes, who decides the sequence of these subframes. The Fading parameters are available for Advanced LTE and Advanced LTE-A TDD. 10 ms radio frame, 1 ms sub frame. The resulting capacity gain equals the “spectral efficiency gain x spectrum used”. simplified LTE TDD frame structure and sug-gested keeping only one optimized frame struc-ture for LTE TDD mode. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. < PRACH Preamble Format >. Downlink Uplink Frame. LTE supports two radio frame. 4. Application. MHz spectrum, we have to use this 20 MHz bandwidth for both DL and UL. In TDD (Time division duplex) technique we are using, same frequency or frame for both DL and UL but at a different time. steps required to estimate synchronization structures that are likely unique to Starlink. In the case of TDD operation (frame structure type 2, middle part of Figure 5. The Fading parameters are available for Advanced LTE and Advanced LTE-A TDD carriers only. 2. The useful symbol time is Tu = 2048 ⋅ Ts ≈ 66. synchronise with Existing TD LTE networks. In case of co-site deployment, slot- and frame structures may be aligned to simplify cell search and inter. FDD and TDD LTE networks have been deployed on all continents. Key to many 5G features is the fact that the subcarrier spacing in 5G NR can take not just one value, 15 kilohertz in LTE, but powers of 2 multiples of 15 kilohertz up to 240 kilohertz as shown on the first line. · Time slot size= 0. Part 2, Advanced topics in LTE 11:00 – 12:30 The LTE MIMO modes Codebook-based precoding Closed. For LTE TDD, the frame configuration 2 is the most widely used frame structure, i. 7 μs. The slot type can be changed. Frame Structure Type 1. 3 GHz TDD technology in [15] and. it means the start of the LTE frame is found and frequency. See full list on rfmw. LTE TDD frame 36. 5 milliseconds. Figures 1 and 2 show the frame structures referenced in Table 1 . It is a TDD type of frame structure which is a natural choice since ETSI band 54 and FCC band 902–928 MHz are both unpaired bands. Figure 3 shows the frame structure for LTE in FDD mode (Frame Structure Type 1). Each subframe has two slots. KR20160137999A - Method and apparatus for determining a flexible subframe type in a lte-tdd system -. This ingenious method enables full-duplex (simultaneous) communication over a half-duplex (serial-binary) link. Technical Overview of 3GPP LTE | Hyung G. 211. When operating in TDD mode, we have to clearly define on exactly when to expect the transmission and when to expect the reception. 2 μs. that supports both TDD and FDD communication modes. · Sub-frame size= 1 ms. Double-click or use the drop-down menu to set the system bandwidth and number of Resource Blocks (RB). Carrier Aggregation in TDD. DL Control Channel. – Frame structure type 1 (FS1): FDD. TheThe LTE frame structure for the FDD and TDD schemes was discussed in Chapter 9. 2. cyclic prefix). One sub frame is composed of 7 normal time slots used for downlink/uplink and 3 special time slots. Unique Feature of 5G Subframe comparing to LTE : Multiple. LTE defines a basic unit of time: In the time domain, both uplink and downlink are organized. N TA,offset for a TDD uplink transmission is. 7 to 12. ITU Pedestrian A channel and ITU. 2. Frame structure type 1 is applicable to both full duplex and half duplex FDD. Type 1: FDD : Frequency Division Duplex. e. A method for use in a cellular communications system, in which system the traffic is sent in frames, each frame comprising a first number of subframes, with a second number of said subframes being available for at least either uplink or downlink traffic, according to which method at least one of said second number of subframes is made to. The frame structure is divided into three types: FDD, TDD, FDD and TDD. Figure 1 shows frame structure type 1, which can be used in either full-duplex or half-duplex FDD mode. Accordingly, LTE supports two kinds of frame structures: frame structure type 1 for the FDD mode and frame structure type 2 for the TDD mode. 3. Learn the basics behind 5G NR waveforms, frame structure, and numerology. Some parameters do not apply to the Basic LTE PRACH and Basic LTE-A PRACH. LTE Physical Layer 2 radio frames are supported: 1. The TDD guard period must be long enough for the farthest NB of which the signal still could be seen. 75% from 280 Mbit/s to 332. g. 첫째로 Fig. Can schedule 1 DL and multiple UL sub-frame at a time. 8. In LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. NR frame structure supports TDD and FDD transmissions and operation in both licensed and unlicensed spectrum. LTE TDD frame structure is shown . It is well understood in the industry that multiple overlapping LTE-TDD deployments in the same band can coexist if they align their frame boundaries and use the same TDD configuration. TS0 is always assigned as the downlink direction an conveys control messages such as the broadcast channel (BCH) while TS1 is always allocated as uplink. The LTE superframe supports the following configurations: Table 4: LTE TDD uplink-downlink configurations Uplink-downlink configuration. 15. cyclic prefix). PCFICH and PDCCH. Just take a look at the overall uplink slot structure. There are seven possible configurations for LTE TDD frame as shown below. This video looks at OFDM waveforms, and the different subcarrier spacings supported in 5G NR. In this tutorial, TDD frame structure below will be used, which is a DDDSU slot pattern with 2. Apart from some smaller differences in the frame structure and mapping of some physical signals, the overall physical layer processing (e. However the system structure of LTE TDD is different from of that in LTE FDD. Download scientific diagram | LTE frame structure in FDD mode: 7 OFDM symbols with normal CP [7]. 5G TDD. Downlink and uplink transmissions are organized in the form of radio frames with 10 ms duration (Fig. At least one of said second number of subframes is made to comprise at least three parts, as follows:. The LTE frame is formed of 10 subframes (SF) of duration 1 ms each and sub-divided into 14 OFDM symbols. Note the similarities to the LTE standard for the 20 MHz transmission mode . Finally, each subframe is split into two timeslots, each with a duration of 0. We propose a frame structure design method that implements a shorter transmission time interval. The uplink edge rate increases from 0. LTE-TDD and NR-TDD CBSDs, GAA channelization and SAS-CBSD protocol extensions. 1 frame은 10 개의 subframe으로 구성되고. N/A. - available for PMCH (Physical Multicast Channel) LTE Resource Grid. 211 4 Frame structure). The NG-RAN includes new generation LTE eNodeB (ng-eNB) and 5G NodeB (gNB), which are responsible for the radio functions, e. Hi All,There are lot of new member joined so i am providing the links of ORAN videos whi. 331 v15. LTE TDD is designed to co-exist with 3GPP TD-SCDMA, and as a result, uses the same frequency bands and frame structure. in 1 slot, the number of symbols are fixed that is 14-with normal cyclic prefix (CP) and 12-with extended CP. Type 2: used for the LTE TDD systems. Type 1 LTE Frame Structure. The current version of the document focuses on Band 48 [11] LTE-TDD using Frame Structure 2 (FS2) The NR frame structure supports TDD and FDD transmissions and operation in both the licensed and the unlicensed spectrum. LTE Frame Structure Figure 1 describes the LTE frame structure for TDD mode [4]. The invention provides a method for transmitting downlink reference signals in a time division duplex (TDD) system. Root ZC sequence order for. TDD stands for Time Division Duplex where as FDD stands for Frequency Division Duplex. · It consists in a category of Frame 2. One TDD frame is composed of í µí± = 10 subframes, and the time length of each subframe is 1 millisecond. Time Division Duplex Wireless is a fundamental technology for 5G deployments around the world. 5GHz typically increases from 1. 0 LTE TDD Subframe Configuration Feature ISSUE 1. It includes support for mobile broadband data, mission-critical communication, and massive machine communication. 811 subscribers. Here D-is downlink, S-for Sp e-cial sub frame and U - for Uplink. 6 Conclusion. The structure of LTE TDD frame is defined by the Uplink/Downlink Configuration, that specifies which subframes are configured as downlink, which are uplink, and which are special subframes,. Slot Structure: In NR, the number of OFDM symbols per slot are fixed (= 14 with normal CP and =12 with extended CP) In LTE, the number of slots per subframe is fixed (= 2). FDD has a Type1 frame structure and TDD has a Type 2 frame structure. To introduce subslots into the TDD structure without impacting the overall subframe structure would mean limited gain, and to change the overall frame. Subframe is of fixed duration (i. They are chosen to be the same as in LTE, thereby allowing for better LTE-NR co-existence. In LTE, DL and UL transmissions are organized into radio frames of 10 ms each. Download scientific diagram | LTE-TDD frame structure from publication: A Study on Channel Estimation Algorithm with Sounding Reference Signal for TDD Downlink Scheduling | Coping with the limited. 10 ms radio frame, 1 ms sub frame. However, with static LTE-TDD, it is difficult to fulfill fast traffic adaptation, leading to the underutilization of base station resources. Each radio frame of length consists of two half-frames of length each. 3GPP LTE Frame Structure 1, Applicable to TDD and FDD Note (1) Note to Figure 1: (1) For more information, refer to 3GPP Technical Specification 36. In addition, LTE air interface supports both frequency division duplexing (FDD) and time division duplexing (TDD). · Radio frame size= 10 ms. In 5G/NR, we don't have any. 2. 2. 4 frames are available only if the Radio Allocation Period is 4, 8, 16, or 32. 10 – Frame structure of transmission signal for LTE-TDD. balance between resolution of channel quality estimation and. LTE frame is 10 ms in duration and consists of 10 subframes. OFDM symbol duration reduces with increased SCS -> since the number of. the amount of signaling overhead. • Time domain structure (FDD) One frame, T frame =10ms One subframe, T subframe =1ms One slot, T msfeature is the frame structure, which introduces a special subframe. The HI all,Please go through video of LTE Frame Structure (FDD and TDD). • In UMTS TDD, both uplink and downlink shares same frequency band at the same time period. Overview-TDD: Frame Structure Type 2 < TDD LTE Frame Structure > Followings are examples for various TDD UL/DL configurations. The type 1 structure (Fig. Additional information on other system parameters is also listed in Table 2. 12 to enable features such as aggregation of carriers between time-division duplex (TDD) and frequency-division duplex (FDD) frame structures. LTE (telecommunication) In telecommunications, long-term evolution ( LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM / EDGE and UMTS / HSPA standards. 9 PDSCH REs in1 radio frame and 2 Tx antennas, TDD mode 0. The concept would be similar to legacy LTE TDD Subframe configuration, but main differences from LTE TDD subframe configuration are. Under the proper design of frame structure, we showed that the proposed scheme is compatible with LTE-A protocol, and the collision with LTE-A signal can be prevented. Here D-is downlink, S-for Sp e-cial sub frame and U - for Uplink. . Comparison between FDD and TDD frame structure in SC-FDMA Abstract: Long Term Evolution (LTE) is the largest wireless communication technology which renders substantially increased data rates to gain higher efficiency in multimedia system. There are two types of LTE frame structures. Time Division Duplex Wireless is a fundamental technology for 5G deployments around the world. The radio frame is represented in the LTE Toolbox™ product by the use of a succession of 10 cell-wide settings structures with the NSubframe field set from 0 through 9 in each case. 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. 4 LTE Frame Structure The figure below shows the frame structure for LTE under Time division mode (TDD) Type 2 and Frequency Division mode (FDD) Type 1. 9, 1. 7 μs. However, regardless of numerology the length of one radio frame and the length of one subfame is same. Number of. One of these feature is Uplink Data Compression, UDC. Less. LTE Frame Structure Figure 1 describes the LTE frame structure for TDD mode [4]. Each radio frame will have a total of ten subframes, each with two time slots. The n78 band’s popularity is due to its relatively common availability, compared to lower cellular spectrum (below 2700MHz) already widely in use by 3G and 4G networks. , the latency, and impact the capacity. At least one of said second number of subframes is made to comprise at least. 11 – LTE-TDD PBCH measurement example. 4G/LTE - PHY Channel PSS (Primary Synchronization Channel). , OFDMA frame structure, PUSC permutation scheme in downlink and uplink subframes, ranging, and channel coding with tail-biting. OFDMA and Downlink Frame Structure Details. Learn the basics behind 5G NR waveforms, frame structure, and numerology. Instead, we can define the pattern in much more flexible way using several parameters as shown below. In LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. 8. Type 2: used for the LTE TDD systems. Fig. Calculation: 1 Subcarrier of PRACH preamble =1. This overview covers both LTE-Advanced FDD Type 1. 2 Challenges in deployment in 2300 MHz band 5. · Radio frame size= 10 ms. PMP frame to this LTE frame, the downlink start has to align to the beginning of subframe 4, not subframe 0. Depending on configuration, they can concatenate multiple DL subframe and add only one UL control in the last subframe. 1 shows an example of such TDD configuration structure in LTE with T= 10 [2]. In LTE TDD, there are 7 predefined patterns for UL and DL allocation. They are chosen to be the same as in LTE, thereby allowing for better LTE-NR co-existence. Radio frames and subframes are of fixed lengths. The slot is of 0. Common frame structure eliminates the need of guard band between operators. FDD LTE is ideal for symmetric traffic, while TDD LTE is ideal for asymmetric traffic. Frame-Structure in LTE. 5 ms. With this shift, the sequence of subframes in the LTE frame becomes D, D, S, U, U, which is the same structure of the Cambium PMP frame (downlink, turnaround time, uplink). package to model commercial 4G LTE systems is developed. LTE uses OFDMA for the downlink, with a fairly simple frame structure, and SC-FDMA for the uplink. Type 2: used for the LTE TDD systems. In TD-SCDMA a super-frame of 720 ms duration is made of 72 radio frames of 10 ms duration each. 1- Providing UE with Cell-Specific Slot format Configuration (tdd-UL-DL-ConfigurationCommon) 2- Providing UE with dedicated Slot format configuration (tdd-UL-DL-ConfigurationDedicated) 1- : RRC : tdd-UL-DL-ConfigurationCommon. The LTE Application framework supports the following (partially fixed) configurations: Bandwidth mode: 20 MHz (100 PRBs) Cyclic prefix configuration: Normal cyclic prefix; Frame Structure: Type 1—FDD; Type 2—TDD. As LTE FDD is full duplex system, means both the downlink and uplink transmission happens at the. Time Division Duplex (TDD) accomplishes this using different time slots for uplink and downlink signals over the same frequency. LTE frame structures used for TDD 36. Very Basic understanding of Frame , subframe , slots and. In case of co-site deployment, slot- and frame structures may be aligned to simplify cell search and inter. Frame structure Type 3N builds on the 3GPP frame structure with the addition of the new nframe concept. subframe is transmitted or uplink. These are; - Type 1 FDD (Frequency Division Duplexing) - Type 2 TDD (Time Division Duplexing) Type 1: It is designed for frequency division duplex, and is valid for both half duplex, and full. Uplink and downlink configurations are used to create subframes (0 to 6). , 3:1 DL/UL ratio with 5 ms DL/UL switching period. 4/3/5/10/15/20 MHz. Downlink and uplink transmissions are organized in the form of radio frames with 10 ms duration (Fig. keysight. LTE-TDD systems provide 7 different semi-static UL-DL configurations of an LTE frame to offer asymmetric DL-UL allocations (see Table II), hence providing DL-UL allocation ratios that vary from 4:6 to 9:1 (the number of DL-UL subframes) [12]. the cells must use the same TDD configuration; the deviation in frame start timing between cells must be below a maximum value specified as cell phase synchronization accuracy in the 3GPP. from publication: Robust Doubly-Differential Primary Synchronization Approach for 3GPP LTE Systems. 즉, 1개의 Radio Frame은 10개의 Subframe!! 여기서 1ms의 Subframe 길이가 TTI (Transmission. 5), there is a single carrier frequency and uplink and downlink transmissions are separated in the time domain on a cell basis. LTE (telecommunication) In telecommunications, long-term evolution ( LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM / EDGE and UMTS / HSPA standards. 4) is applied to Time Division Duplex (TDD) mode maintaining only full duplex operation. Fig. Further each radio frame is divided into two sub frames each of 5ms. Downlink. 5 ms. 7 Furthermore, unlike LTE where the uplink-downlink allocation does not change over time, 8 the TDD operation for NR is designed with dynamic TDD as a key technology component. 1ms) where as slot length varies based on subcarrier spacing and number of slots per subframe. 3GPP defined seven frame structures for LTE-TDD, where only a limited number of configurations allocate more transmission time to the DL than the UL and have a 5 ms periodicity, which is necessary for compatibility with NR for quicker response. Choose a configuration with more “D”s in the frame means greater proportion of Downlink Data (normal for most Internet /ISP applications). 9 – Frame structure LTE-TDD type 2 (for 5€ms switch-point periodicity) Figure€E. For the examples of TDD resource grids for each Subframe DL/UL Configuration and Special Subframe Configuration, see Frame Structure Frame Type 2 Overview section. 8A CN201580008676A CN105993137A CN 105993137 A CN105993137 A CN 105993137A CN 201580008676 A CN201580008676 A CN 201580008676A CN 105993137 A CN105993137 A CN 105993137A Authority CN China Prior art keywords frame flexible sub index sub radio frames Prior art date 2014-02-13. 5 ms or 10 ms periodicity. 21). CN105993137A CN201580008676. You might have experience how much complicated (confusing) it become about HARQ process in LTE in TDD mode. given in Annex 1 is compatible with the LTE-TDD frame structure configuration no. TDD frame structure type is used. The frame consists of two "half-frames" of equal . The present invention provides systems, apparatuses, methods, and computer-readable media for a User Equipment (UE) device comprising one or more processors configured to determine, based on a DL signal in an LTE-TDD radio frame, that an eNB has evaluated that the radio frame is valid based on a Cat-2 Listen Before Talk (LBT) procedure; and in. 4 to 20MHz, and aggregation of multiple channels), both in FDD and TDD bands. In TDD mode, the SF is either of type DL, UL or special (Spc). Compared with the 3. Introduction to SC-FDMA and uplink frame structure. This video has been taken from our LTE Air Inte. 9G (Pre-4G) cellular technology Now sold as 4G. NR uses flexible subcarrier spacing derived from basic 15 KHz subcarrier spacing used in LTE. Single Ack/Nack corresponding to 1DLsub frameFrequency Division Duplex (FDD) and Time Division Duplex (TDD) are the prevailing duplexing scheme in LTE that provides deployable tractability according to spectrum assignation. TDD version is used where both uplink and downlink data rates are asymmetrical. TDD Frame Structure LTE’s frame structure ‘type 2’ supports Time Division Duplex (TDD) mode. Here. 1; and Type 2, which is used in TDD and is the minor mode [24]. The frame can be dynamically configured to any one of the preset configurations shown, depending on the instantaneous data transmission requirement. 6 MHz and 3. 2. Edition. Transmission in TDD is not continuous because there is a hardware delay (for both UE and eNodeB) in switching between UL and DL that needs to be compensated. LTE TDD is designed to co-exist with 3GPP TD-SCDMA, and as a result, uses the same frequency bands and frame structure. At least one of said second number of subframes is made to comprise at least three parts, as follows:. Hence there are total 20 slots in a radio frame. LTE Downlink Channel Estimation and Equalization. Instead, we can define the pattern in much more flexible way using several parameters as shown below. 10 ms radio frame, 1 ms sub frame. Radio frames and subframes are of fixed lengths. DL Control Channel. The frame structure is different for FDD and TDD topologies. The screen shot below shows the parameter choices for a DL-SCH n channel.