lte tdd frame structure. 1 provides an illustration of an LTE FDD and TDD frame structure as an example of an air interface with FDD and TDD modes. lte tdd frame structure

 
 1 provides an illustration of an LTE FDD and TDD frame structure as an example of an air interface with FDD and TDD modeslte tdd frame structure  An apparatus for a user equipment (UE) device, comprising baseband circuitry having a radio frequency (RF) interface configured to receive downlink (DL) signals and transmit uplink (UL) signals during a succession of long-term evolution (LTE)—time division duplex (TDD) radio frames, and one or more processors configured to: determine, based on a

LTE Devices Growth in India: Band 40 and 41 4. PCFICH (Physical Control Format Indicator Channel) PHICH (Physical Hybrid ARQ (Automatic Repeat reQuest) Indicator Channel) PDCCH (Physical Downlink Control Channel) Available for PDSCH (Physical Downlink Shared Channel) TDD guard period in special subframe. Figure 3 shows the frame structure for LTE in FDD mode (Frame Structure Type 1). Under the existing LTE TDD frame structure , which subframe can be UL or DL is fixed within a radio frame . (Preamble format 4 is used only in TDD LTE. In the special slot, symbols allocated for downlink, gap and uplink are 10:2:2 respectively. However, unlike LTE-U, LAA use a special physical layer frame structure called Frame Structure Type 3 which didn't exisit before. In 5G/NR, we don't have any predefined pattern. 5 GHz range. Figure 3 shows the frame structure for LTE in FDD mode (Frame Structure Type 1). 9, 1. · Each Radio frame consists two half frames. 1, TDD frames of different cells are aligned in the time domain. Initial Cell Search and Cell Selection. • The figure-3 depicts UMTS TDD frame structure. Figure 1 show s the frame structure fo r LTE TDD . LTE Parameters and Downlink Modulation. This applies for the currently-transmitting Starlink satellites (versions 0. Hi All,There are lot of new member joined so i am providing the links of ORAN videos whi. Made up of 62 Zadoff Chu Sequence Values; Used for Downlink Frame Synchronization; One of the critical factors determining Physical Cell ID;. At least one of said second number of subframes is made to comprise at least. tdd UL/DL Common Configuration (tdd-UL-DL-configurationCommon) in Detail . frame [9]. At least one of said second number of subframes is made to comprise at least three parts, as follows:. The target figures for data throughput in the downlink is 1 Gbps for 4G LTE Advanced. International Search Report for PCT/CN2008/001840 dated Jan. LTE-TDD configurations 2 (and maybe 1) are compatible with. 2 TDD PDSCH Single Antenna Port Performance with 1 PRB. One of the design principles of 5G NR has been the ability to coexist within the LTE physical layer structure to allow for sharing the existing 4G spectrum with new 5G devices. Each half-frame consists of five subframes of length . 5 ms. 5 ms, T FA is the radio frame alignment which depends on various configurations of the TDD frame structure, and the TTI duration is 1 ms, hence, the user-plane latency of the TDD mode can be written as T USER-PLANE = 3. balance between resolution of channel quality estimation and. N/A. Each radio frame of length consists of two half-frames of length each. LTE Physical Layer 2 radio frames are supported: 1. In this paper, we analyze the performance of SC-FDMA and OFDMA in LTE Frame Structure based on Peak to Average Power Ratio (PAPR) analysis. 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. 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)). One sub frame is composed of 7 normal time slots used for downlink/uplink and 3 special time slots. Nzc is determined by the following table. Unique Feature of 5G Subframe comparing to LTE : Multiple. A. 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. As LTE FDD is full duplex system, means both the downlink and uplink transmission happens at the. Even under dynamic TDD configuration , the TDD configuration can only change every 10 ms ( one radio frame ) . LTE has radio frame of duration 10ms consisting of 10 subframes. codes in LTE). Figure ‎6. The Fading parameters are available for Advanced LTE and Advanced LTE-A TDD. 5 GHz band, the uplink peak data rate increases by 18. Therefore, the accuracy. In 5G/NR, we don't have any. Uplink and downlink configurations are used to create subframes (0 to 6). 331 v15. 211). NR uses flexible subcarrier spacing derived from basic 15 KHz subcarrier spacing used in LTE. 7 μs. 7. Technical Overview of 3GPP LTE| Hyung G. The following text shows the frame structure of each type. 2 μs. 5G NR TDD self-contained slot structure in action Three examples showcasing faster TDD switching for low latency DL reference signals (DL DMRS) & UL Reference + Sounding (UL DSMR, SRS) not showed for simplicity. In LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. – Frame structure type 2 (FS2): TDD. Frame Structure, Bandwidth Mode, CP Mode, and Physical Resource Grid. Conformance Test Setup. So, it is very important to understand the slot structure and other details about slot-based scheduling etc. NOTE: There are much more information you need to know about the numerology in addition to this table. Time/frequency frame structure and definition of sidelink resource pool for NR V2X TDD. Introducing sTTI in LTE has conflicting design aspects with regards to the frame structure. synchronise with Existing TD LTE networks. , the latency, and impact the capacity. However, for this to work all TDD networks, either LTE or 5G, operating in the same frequency range and within the. Frame-Structure in LTE. 1. To set up a fixed reference channel (FRC), for an Advanced LTE TDD Uplink carrier, click the Wizard button Uplink Setup node to open the PRACH Wizard. In LTE base station is referred as eNodeB and mobile subscriber is referred as UE. Frame Structure Candidates . Figure 1: LTE Generic Frame Structure [3] 2. In this tutorial, TDD frame structure below will be used, which is a DDDSU slot pattern with 2. LTE offers a flexible range of channel bandwidth (1. Figure 9. This section only discusses how to. The scheduling based on the SIB (System Information Blocks) transmission. Signal ModelTime Division Duplex (TDD) accomplishes this using different time slots for uplink and downlink signals over the same frequency. LTE TDD Frame Configuration These first three groups of settings apply to all basic carriers. NOTE: * E-UTRA TDD UE will have a relatively lower Noise Figure since it does not have a duplexer. A flexible radio frame structure for both FDD and TDD is proposed. OFDMA Downlink. 0 as follows : TDD-UL-DL-ConfigCommon ::= SEQUENCE 04/02/2023 10 Types of Frame Structure in LTE: • Types of Frame structure in LTE: 3GPP defines two types of frames based on the duplexing scheme used. In LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. This is known as synchronization and refers to sharing a common clock, phase reference and the same frame structure. 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. channel coding. 370/210: 20080144530: Method, device, system and software product for alternative time division duplex frame structure optimization: 2008-06-19: Che et al. FDD LTE uses a paired spectrum, while TDD LTE uses an unpaired spectrum. LTE, TDD frame structure uses. The remaining six symbols have a cyclic prefix of length TCP = 144 ⋅ Ts ≈ 4. Two types of frames are defined for LTE: Type 1, which is used in FDD and is the dominant mode of operation as shown in Fig. · Time slot size= 0. Signal Model Time Division Duplex (TDD) accomplishes this using different time slots for uplink and downlink signals over the same frequency. 11. Second, we present a detailed characterization of the Star-link downlink signal structure in the 10. 1, 2007, pp. 36. 5G Waveforms, Frame Structure, and Numerology | 5G Explained. 7 μs. 211 frame structure type 2 (DL / UL / SSF) Correct choice of Configuration value is essential when setting the UL/DL ratio for CableFree LTE networks using TDD bands. A phone must typically perform the following tasks (Figure 5): Acquire a signal on a given LTE carrier frequency. Compared with the 3. Each radio frame of length Tf = 307200*Ts = 10 ms consists of two half-frames of length Tf = 153600*Ts = 5 ms each. Choose a configuration with more “D”s in the frame means greater proportion of Downlink Data (normal for most Internet /ISP applications) Frame Structure. 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. As a consequence, as the OFDM symbol duration is the. 5 ms. All networks operating within the 3. Type 1: FDD : Frequency Division Duplex. 4. OFDM with a cyclic prefix is the basic modulation scheme selected to combat severe frequency-selective multipath fading. This article describes OFDMA basics, OFDMA frame structure,OFDMA symbol, OFDMA Physical layer as per IEEE 802. how CCIM can solve the problems that appear due to the peculiarity of this structure. One slot made up of 7 small blocks called 'symbol'. 5G opens up new spectrum by the introduction of Sub-6GHz and mmWave, which can also be deployed as non-standalone with LTE, thus, creating new challenges for carriers to deliver a ubiquitous user experience,LTE, LTE Advanced, Gigabit LTE 2020s Wireless Edge 5G New Radio (NR) 3 Delivering on the 5G vision. Refer LTE stack >>. Channel Mapping and UE Categories. Long Term Evolution. 4. 4) is applied to Time Division Duplex (TDD) mode maintaining only full duplex operation. For the normal mode, the first symbol has a cyclic prefix of length TCP = 160 ⋅ Ts ≈ 5. Very Basic understanding of Frame , subframe , slots and OFDM symbols1. Under the existing LTE TDD frame structure , which subframe can be UL or DL is fixed within a radio frame . 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 different 4G LTE deployment methods that are used in different environments. 4 LTE mobile device availability summary 4. 5G NR frame Structure. Just take a look at the overall uplink slot structure. Frame Structure Candidates . To configure the downlink signal in this slot pattern, two separate DL-SCHs will be needed to represent two different channel. Can Schedule 1 DL and 1 UL subframe at a time. The 5G NR architecture comprises next-generation RAN (NG-RAN) and 5G Core Network (5GC) [], both described in the following subsections. LTE,SRS, Sounding Reference Signal Tweet4Technology: LTE 5G-NR Wireless Technology Blogs. There are three types of Frame Structure : Type 1 for FDD, Type 2 for TDD, Type 3 for LAA. The manner of transmitting SRS in LTE TDD is mainly the same as that in LTE FDD. the amount of signaling overhead. 4G/LTE - RACH. One of the most fundamental TDD features is the specific TDD frame structure with the introduction of the special subframe. 11, the total one-way processing time is 2. 1 The NG-RAN. Frame. One such specific consideration is for TDD operation where the existing TDD frame structure in LTE up to Release 14 was based on downlink subframes, uplink subframes and special subframes. Each subframe has two slots. Two duplex schemes FDD and TDD are supported. We propose a frame structure design method that implements a shorter transmission time interval. (FDD) or unpaired (TDD) spectrum allocation • Mobility – Optimized for 0~15km/h – Support with high performance for 15~20 km/h. In TDD (Time division duplex) technique we are using, same frequency or frame for both DL and UL but at a different time. I claim: 1. A subframe consists of two consecutive slots (0. Type 2: used for the LTE TDD systems. 2. TD-SCDMA frame structure is shown in figure 2, which depicts frame hierarchy. LTE frame structures used for TDD 36. , OFDMA frame structure, PUSC permutation scheme in downlink and uplink subframes, ranging, and channel coding with tail-biting. The flexible TDD design of 5G NR is described in Section 5. In this paper, we study the frame structure design for low latency communications in 5G TDD. 4. • The figure-3 depicts UMTS TDD frame structure. 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). The LTE superframe supports the following configurations: Table 4: LTE TDD uplink-downlink configurations Uplink-downlink configuration. LTE-TDD and NR-TDD CBSDs, GAA channelization and SAS-CBSD protocol extensions. 4 frames are available only if the Radio Allocation Period is 4, 8, 16, or 32. 5G TDD. Spectral efficiency at 3. – Frame structure type 2 (FS2): TDD. 5 ms. The resulting capacity gain equals the “spectral efficiency gain x spectrum used”. To know more on LTE TDD vs FDD, visit our page on LTE TDD Vs FDD modes and go through LTE frame structure in both of these modes. 7 μs. 2. 5 ms or 10 ms periodicity. Root ZC sequence order for format 0-3. Therefore, the accuracy. IWSON / VTC2015 Summary In LTE-TDD, the amount. package to model commercial 4G LTE systems is developed. 7 μs. Apart from some smaller differences in the frame structure and mapping of some physical signals, the overall physical layer processing (e. efficiency and coverage because of the frame structure, and the nature of the spectrum unutilized for TDD being deployed in high bands. LTE TDD is designed to co-exist with 3GPP TD-SCDMA, and as a result, uses the same frequency bands and frame structure. In frame structure Type 1, each 10 ms radio frame is divided into 10 equally sized subframes. The LTE TDD frame is transmitted after the starting time of the LTE TDD frame arrives. Each frame is divided into ten equally sized subframes. In the TDD duplexing mode, a single bandwidth is shared between uplink and downlink, with the sharing being performed by. · Time slot size= 0. The LTE-TDD frame structure can be adjusted to have either 5ms or 10ms DL-UL switch point periodically. Radio frames and subframes are of fixed lengths. 1 provides an illustration of an LTE FDD and TDD frame structure as an example of an air interface with FDD and TDD modes. PCFICH and PDCCH. Fig. Type 1: used for the LTE FDD mode systems. 5 ms. LTE DL Frame Structure in a Nutshell. 2. “10ms” version, and gives greater opportunity for uplink/downlink flexibility. Fig. In TDD spectrum, for small/isolated cells it is possible to use dynamic TDD to adapt to traffic variations, while for large over-the-rooftop cells, Frame structure. Figure 7A illustrates a CA frame structure 700 for a TDD-TDD carrier aggregated PUSCH-less cell arrangement for data transmission between a UE 115 and BS 105 according to some. There are two types of LTE frame structure: Type 1: used for the LTE FDD mode systems. LTE TDD frame 36. Hence there is guard period between transmission and reception to avoid interference. that supports both TDD and FDD communication modes. Frame Stracture. · It consists in a category of Frame 2. Two figures are created illustrating the received and equalized frame. Frame Stracture. 5 ms or 10 ms periodicity. LTE: Key Features. • A radio frame has duration of 10 ms. 1ms) where as slot length varies based on subcarrier spacing and number of slots per subframe. 7K views 2 years ago. prodevelopertutorial May 17, 2020. 7 μs. 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. Choose. In LTE TDD, there are 7 predefined patterns for UL and DL. The radio frame of 10 ms are transmitted continuously as per TDD topology one after the other. As shown 5 ms periodicity frame have two “S” sub frame and 10 ms framesIn LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. – Frame structure type 1 (FS1): FDD. A. when μ = 0. 2. LTE also support both TDD and FDD, but unlike the single frame structure used in NR, LTE uses two different frame structures. 11 and Rel. Choose a configuration with more “D”s in the frame means greater proportion of Downlink Data (normal for most Internet /ISP applications). Frame Structure and Crossed Slots LTE-TDD frame consists of 10 sub-frames of 1 ms each. The TDD guard period must be long enough for the farthest NB of which the signal still could be seen. CMCC,CATT, etc. In each subframe, there are two switching. The slot is of 0. Instead of following a fixed TDD frame structure over time like LTE, 5G NR can rely on both semistatic configuration and dynamic indication to claim which slots and symbols are used for uplink and which slots and symbols are used for downlink. Configuration of special subframe Figure 24. Here D-is downlink, S-for Sp e-cial sub frame and U - for Uplink. Further each radio frame is divided into two sub frames each of 5ms. Figure€E. 2. 1. One way to avoid cross-link interference is to ensure that all base stations are either transmitting simultaneously or receiving simultaneously. 5 ms. 5 ms. In case of co-site deployment, slot- and frame structures may be aligned to simplify cell search and inter. 6 bps/Hz for LTE-A 2×2 to 7 bps/Hz for 5G NR 64TRX. N TA,offset for a TDD uplink transmission is. 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]. 8MHZ. 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. For the normal mode, the first symbol has a cyclic prefix of length TCP = 160 ⋅ Ts ≈ 5. In contrast to mainstream commercial LTE software packages, the developed package is specifically tailored to accurately model mission critical IoT applications and above all fully conforms to commercial 4G LTE signaling and QoS standards. The analysis sought to identify and quantify the similarities and differences within the overarching LTE specification documents as they pertain to the implementation require-. Probably what I do as the first step is to describe each part of the map in a verbal form Overview-TDD : Frame Structure Type 2 < TDD LTE Frame Structure > 5/26 4/19/22, 2:11 PM ShareTechnote Followings are. The LTE frame is formed of 10 subframes (SF) of duration 1 ms each and sub-divided into 14 OFDM symbols. For up link: SC-FDMA: Single Carrier Frequency Division Multiple Access. 2. 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. frame structure for OFDM systems . Frame Structure Type 2: TDD. In LTE, each downlink subframe (and the DwPTS in the case of TDD; see Section 5. g. In a number of countries, there are legacy LTE TDD or WiMAX networks in the 3. In this tutorial, TDD frame structure below will be used, which is a DDDSU slot pattern with 2. from publication: Robust Doubly-Differential Primary Synchronization Approach for 3GPP LTE Systems. 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. This ingenious method enables full-duplex (simultaneous) communication over a half-duplex (serial-binary) link. • A radio frame has duration of 10 ms. 8 PDSCH REs in1 radio frame and 1 Tx antenna, TDD mode 0. Introduction to SC-FDMA and uplink frame structure. The duration of each subframe is 1 ms. 2 MHz for interworking with LCR TDD, but these were removed when the LTE TDD frame structure was aligned with the FDD frame structure rather than the TD-SCDMA frame structure from UMTS. UL Control Channel. A TDD frame structure similar to that in [39, Figure ] is considered for all the BSs and UEs with synchronous operation. Figure 1 shows frame structure type 1, which can be used in either full-duplex or half-duplex FDD mode. The invention provides a method for transmitting downlink reference signals in a time division duplex (TDD) system. There are two types of LTE frame structure: Type 1: used for the LTE FDD mode systems. frequency band (Band n78) to define common TDD frame structures at national level. 8. 7 μs. 211 V1. 2 μs. In LTE TDD, we defined 7 predefined pattern for UL and DL allocation in a radio frame. 2–1) Symbol level TDDResource Block of RACH in LTE Frame Structure : Preamble length is 6RB , 1 RB=180KHZ, so 6RB=1. Each frame is divided into 10 subframes of 1 millisecond, and the subframe is further divided into slots according to numerology. Time Division Duplex Wireless is a fundamental technology for 5G deployments around the world. BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments of the invention are disclosed in the following detailed description and the accompanying draw 1ngS. The frame 402 has two 5 ms half frames 404, and each of the half frames 404 includes five 1 ms subframes 406. OFDM with a cyclic prefix is the basic modulation scheme selected to combat severe frequency-selective multipath fading. Mandatory Guard Period in TDD Bands makes them highly inefficient if used in lower frequency configurationThe LTE TDD frame structure is Type 2. 00In the TDD frame structure of a wireless communication system such as LTE, a single frequency block is shared in the time domain between UL and DL transmission. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. There are two types of LTE frame structures. subframe is transmitted or uplink. In 5G/NR, we don't have any predefined pattern. TDD frame structure type is used. A TDD frame structure is shown in below figure. Refer LTE Frame >>. Carrier Aggregation in TDD. There are seven diferent standardised LTE frame structure configuration. UMTS TDD. 7 GHz band. There are three different kinds of units specified for this frame structure, illustrated in Figure 6. There are seven possible configurations for LTE TDD frame as shown below. 2 μs. TDD LTE is much better in the allocation of traffic than FDD LTE. LTE is designed primarily for full duplex operation in paired spectrum. FDD version is used where both uplink and downlink data rates are symmetrical. 그 위 L2부터는 동일한 규격을 사용한다. The ME7873L LTE RF Conformance Test System supports the LTE frequency bands deployed worldwide, and users can choose the FDD/TDD test functions matching their test terminals. TDD have a special sub frame (1,6) when downlink-to. Hence there are total 20 slots in a radio frame. Figure 1: TD D frame str ucture . in 1 slot, the number of symbols are fixed that is 14-with normal cyclic prefix (CP) and 12-with extended CP. LTE Frame Structure Figure 1 describes the LTE frame structure for TDD mode [4]. The The LTE frame structure for the FDD and TDD schemes was discussed in Chapter 9. An exemplary method includes obtaining an indication of whether a carrier frequency of the NR network coexists with a carrier frequency of a long term. 2 DSUDDDSUDD (10ms duration), where different special subframe “S” configurations are possible such 1EP2479919A1 EP12160504A EP12160504A EP2479919A1 EP 2479919 A1 EP2479919 A1 EP 2479919A1 EP 12160504 A EP12160504 A EP 12160504A EP 12160504 A EP12160504 A EP. Under the flexible frame structure, each radio frame consists of a plurality of slots, and each slot within a radio frame has a flexible slot type. Downlink Uplink Frame TIME. 2. Apart from some smaller differences in the frame structure and mapping of some physical signals, the overall physical layer processing (e. These are Type 1 when FDD is used and Type 2 when TDD is used. 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. Frame Structure Type 1. 3. There are seven possible configurations for LTE TDD frame as shown below. · Radio frame size= 10 ms. As a result, the uplink power level due to SC-FDMA also need to be increased by 2~3dB to compensate for the extra noise due to more spreading. 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. 10 ms radio frame, 1 ms sub frame. In TDD there are. Root ZC sequence order for. Then, 5G-NR is recommended to operate with a TDD DL/UL switching period of 5 ms with the pattern of “DDDDDDDSUU” and the DL/UL ratio of 8:2 to attain synchronization with LTE. LTE supports two radio frame. However, for simulation alignment purpose, a Noise Figure of 9 dB will be used. URLLC within a carrier should be supported , and TDD with flexible UL / DL ratio is desirable . The frame consists of two "half-frames" of equal . One of these feature is Uplink Data Compression, UDC. 3GPP has defined 7 frame structures for LTE-TDD. A radio frame consists of 10 subframes. As an. LTE video tutorials covering OFDM, frame structure, Cell mapping, random access procedure. 2와 같이 프레임 구조 (Frame Structure)가 다르다. 03255) us. Frame Structure Type 1. 5ms, each slot is composed of 7 symbols (normal cyclic prefix), therefore a resource block of 12 subcarriers by 7 symbols occupies one slot. em. 2 μs. 2 Differences between FDD-LTE and TDD-LTE 3. Type 1: Used in LTE FDD Type 2: Used in LTE TDD The following text shows the frame structure of each type. However, employing TDD will lead to a long transmission latency due to the uplink/downlink transmission constraints. Increasing frame configuration; Configuration: 3GPP release: Downlink to uplink switch point periodicity (ms) Subframe number: Number of subframes / frame: 0: 1: 2: 3: 4: 5: 6: 7: 8: 9: D [DL] U [UL] S. 3rd frame is always used for Uplink transmission Time Division Duplex (TDD) accomplishes this using different time slots for uplink and downlink signals over the same frequency. Number of.