Lte Slot Symbol
Menu Path: MeasSetup > LTE Demod Properties... > Profile tab > Edit User Mapping...
- As Figure A.11 shows, the symbols are identical as regards cyclic prefixes in 4G LTE and 5G (n = 0). In fact, the only significant difference is the use of the term ‘slot’. You might recall that 4G LTE allows for an extended cyclic prefix with a length of 16.6 s for environments where the radio signal is subject to an unusually long delay.
- Each subframe in the LTE frame structure can be further split into two slots equal in length, which is T slot= 0:5ms. Within each slot, there are several OFDM symbols and cyclic pre xes. The slots in one LTE radio frame are numbered from 0 to 19.
Symbol – uniquely identified by the index pair (k,l) in a slot. Resource block consisting of multiple RE Physical RB – Normal CP: 12x7 – Extended CP: 12x6 (for 15KHz) and 24x3 (for 7.5KHz) DL Nsymb Tslot l = 0 DL 1 l = Nsymb − RB sc DL RB N N × RB sc N RB sc DL Nsymb ×N (k,l) k = 0 RB 1 sc DL k = NRB N −.
The LTE Allocation Editor dialog is used to define user mappings. There are two different versions of this dialog for both uplink and downlink depending on the RB Auto Detect setting. When RB Auto Detect is selected, the LTE Allocation Editor will only show the parameters needed for successful demodulation.
The lower area of the LTE Allocation Editor shows a graphical representation of the user allocations. You can use this graph to edit the allocations when defining allocations manually. Clicking on an allocation will make the allocation active. Allocations can be moved around by dragging them, and they can also be resized by dragging the circular handles at the corners.
For TDDTime Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period., subframes that do not belong to the current direction are annotated by either 'ULUp Link (reverse link: from cell phone to base station)' (when direction is set to downlink) or 'DLDown Link (forward link: from base station to cell phone)' (when direction is set to uplink).
When overlapping user allocations are defined, an overlapped area will belong to the last user listed in the Composite Include list whose allocation includes that area.
Although the LTE Allocation Editor allows downlink resource block allocations to contain uplink resource blocks in TDD frames, the demodulator will only analyze the part of the allocation that consists of downlink resource blocks and will ignore the part of the allocation that consists of uplink resource blocks.
Downlink
This table lists all the parameters available to set up downlink PDSCHPhysical Downlink Shared Channel user allocations.
Parameter | Description |
|---|---|
| RBResource Block Auto Detect | When RB Auto Detect is selected, the demodulator will autodetect PDSCH user allocations according to the specified RB Auto Detect Mode. See the Downlink user allocations topic for more information about configuring parameters for user allocation autodetection. When RB Auto Detect Mode is set to Power Based, the LTELong Term Evolution demodulator can detect allocations which use either Spatial Multiplexing (SpMux) or Transmit Diversity (TxDiv) precoding, but not both. The Precoding parameter determines which type of precoding the demodulator looks for. For downlink signals, auto detection supports only PDSCH allocations transmitted on C-RSCell-specific RS antenna ports. |
| RB Auto Detect Mode | RB Auto Detect Mode specifies how the LTE demodulator detects user allocations. See the RB Auto Detect Mode topic for more information. |
| Auto-detect Power Levels | When Auto-detect Power Levels is selected, the LTE demodulator will detect the relative PDSCH power level for each user allocation (PA). See the Auto-detect Power Levels topic for more information. |
| Use Per-antenna EPRE | When selected, PDSCH power is specified by the EPRE (Energy Per Resource Element) parameter. When cleared, PDSCH power is specified using the CW0/CW1 Codeword Power parameters. |
Multi-Frame Analysis (single-antenna, TDD only) | Specifies whether to allow multi-frame allocations. When this parameter is selected, allocations spanning two frames can be defined, and the Show Mapping parameter will be enabled. This parameter is only applicable to single-antenna TDD frame type 2 signals (Input > Channels set to 1 Channel or Single I+jQ; Num of C-RS Ports set to 1). |
Show Mapping (single-antenna, TDD only) | Specifies which frame's allocations to show on the RB Mapping graph in the lower section of the LTE Allocation Editor. Each PDSCH allocation can be specified to be either a Frame0 or Frame1 allocation. This parameter is only applicable to single-antenna TDD frame type 2 signals (Input > Channels set to 1 Channel or Single I+jQ; Num of C-RS Ports set to 1). |
| Include | When this check box is selected, demodulation results from the corresponding user mapping are shown on the appropriate traces and included in EVMError vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. calculations. When this check box is cleared, demodulation results for the corresponding user mapping will only be shown on the Frame Summary table. |
| Name | Name of the user allocation in the form UserXX, where XX is a number. |
RNTIRadio Network Temporary Identifier | Radio Network Temporary Identifier for this user. This value is used for demodulating UEUser Equipment (e.g. cell phone)-specific Reference Signals. |
| UE-specific RS | |
Present | Selecting Present will cause the demodulator to search for UE-specific RS. To view antenna beam patterns, see the Antenna Combined Beam Pattern trace. When Present is selected, CDD and Codebook Idx are disabled because codebook and CDDCyclic Delay Diversity (CDD): To avoid unintentional beamforming, the IEEE 802.11n draft standard uses a process known as Cyclic Delay Diversity (CDD), which basically offsets each spatial stream by a different constant, non-coherent delay. The offset considerably lowers the likelihood of correlated signals being transmitted by two or more antennas. This, in conjunction with a pseudorandom scrambler run over the transmitted data bits, ensures that the likelihood of two spatial streams correlating is very low. are only applied to C-RS based MIMOMultiple Input, Multiple Output: A physical layer (PHYPhysical Layer) configuration in which both transmitter and receiver use multiple antennas., not UE-specific RS based MIMO. |
Include | When Include is selected, UE-specific RS will be shown on appropriate traces and included in error metric calculations. |
Power(dB) | Power(dB) specifies the average power of UE-specific RS relative to the 0 dB point determined by the C-RS Power Boost parameter in Downlink Control Channel Properties. |
Port | Specifies on which logical antenna port UE-RSUE-specific Reference Signal is transmitted for the selected PDSCH user allocation. Possible selections are as follows:
|
nSCID | Specifies the scrambling identity when the UE-RS Port is set to Port 7, Port 8, or Ports 7-8. This parameter is autodetected and shown on the DL Decode Info trace as ScID when RB Auto Detect Mode is set to Decode PDCCH. See 3GPP TSTechnical Specification 36.211 v9.10, Section 6.10.3 for more information. |
| Add | Adds a user mapping. |
| Delete | Deletes the selected user mapping. |
| PDSCH | The LTE demodulator can autodetect PDSCH allocations. When RB Auto Detect is selected, the demodulator will perform the type of autodetection specified by RB Auto Detect Mode. When RB Auto Detect is cleared, PDSCH allocations need to be setup manually using the PDSCH parameters listed below. See the Downlink user allocations and RB Auto Detect Mode topics for more information about configuring PDSCH allocations. |
| Precoding | Specifies the type of MIMO precoding performed on the current user's data. The possible choices are Transmit Diversity (TxDiv) and Spatial Multiplexing (SpMux). When SpMux is selected, the parameters No. Layers, No. Codewords, CDD, and Codebook Idx must also be specified. Power Based autodetection can detect allocations using either spatial multiplexing or transmit diversity, but not both. The Precoding parameter determines which type of precoding the demodulator looks for. |
| No. Layers | Specifies the number of layers for the current user. The maximum number of layers allowed for any user in the LTE Allocation Editor is constrained to be less than or equal to Num of Meas Channels. For PDSCH allocations transmitted on C-RS antenna ports, the maximum number of layers is also constrained to be less than or equal to the Num of C-RS Ports. |
| No. Codewords | Specifies the number of code words (1 or 2) for the current user. The selections available are dependent on the number of layers and multiplexing mode, according to the standard. |
| CDD | Specifies the Cyclic Delay Diversity mode for the current user. Possible selections are W/o CDD and Large CDD. When Present is selected (under UE-specific RS in the user allocation table), CDD and Codebook Idx are disabled because codebook and CDD are only applied to C-RS based MIMO, not UE-specific RS based MIMO. See Sections 6.3.4.2.1 and 6.3.4.2.2 in 3GPP TS 36.211 for more information about cyclic delay diversity. |
| Codebook Idx | Specifies the codebook index for the current user. The codebook index determines the precoding matrix. See Tables 6.3.4.2.3-1 and 6.3.4.2.3-2 in 3GPP TS 36.211. When Present is selected (under UE-specific RS in the user allocation table), CDD and Codebook Idx are disabled because codebook and CDD are only applied to C-RS based MIMO, not UE-specific RS based MIMO. |
| Per-allocation Parameters | |
| Couple | Certain parameters can be coupled across all RB allocation groups. Selecting the Couple check box to the right of a parameter will couple that parameter across all RB allocation groups. |
| RB Start | Specifies the RB start boundary of the current allocation group for the current user. |
| RB End | Specifies the RB end boundary of the current allocation group for the current user. |
| Slot Start | Specifies the slot start boundary of the current allocation group for the current user. |
| Slot End | Specifies the slot end boundary of the current allocation group for the current user. |
| EPRE (dB) | Setting the per-antenna Energy Per Resource Element (EPRE) is an alternative way of specifying the CW0/1 Power for a user allocation. EPRE (dB) = 10*log10( (CW0 Power + CW1 Power) / Np ) where Np = number of antenna ports The demodulator assumes that CW0 Power = CW1 Power when EPRE is specified. |
CW0 Mod Type CW1 Mod Type | Sets the codeword modulation type. The possible selections are QPSKQuadrature phase shift keying, QAM16, or QAM64. When the check box to the left of CW0 Mod Type or CW1 Mod Type is selected, the codeword is configured to be active for the currently selected PDSCH user mapping. When the check box to the right of CW0 Mod Type or CW1 Mod Type is selected, the codeword modulation type is coupled across all slots. |
CW0 MCSmodulation and coding scheme Index CW1 MCS Index | Specifies the MCS Index for decoding of the PDSCH in the absence of DCIDownlink Control Information. A value of -1 indicates that the parameter is not used. |
CW0 Power (dB) CW1 Power (dB) | Specifies the expected average power per resource element for symbols that do not contain Cell-specific RS according to the following equation: CW Power = rA(dB) + C-RS Power Boost(dB) When there are multiple antenna ports, the power is split among the antenna ports. For example when there are two transmit antennas and CW0 Power is set to 0 dB, the expected average subcarrier power for CW0 would be -3 dB for each antenna port. This would be the power reported for PDSCH user allocations in the Frame Summary trace. Codeword power is coupled across all slots when the check box to the right of the codeword power is selected. |
Frame Index (single-antenna, TDD only) | Specifies for which frame this allocation is active. Possible choices are Frame0 and Frame1. Multi-Frame Analysis must be selected for this parameter to be available. This parameter is only applicable to single-antenna TDD frame type 2 signals. Input > Channels must be set to 1 Channel or Single I+jQ. |
| Add | Adds an allocation to the selected user. |
| Delete | Deletes the selected allocation. |
Uplink
This table lists and describes all the parameters available to configure user allocations for uplink channels and signals.
Parameter | Description |
|---|---|
| RB Auto Detect | When RB Auto Detect is selected, the demodulator can autodetect PUSCHPhysical Uplink Shared Channel, PUCCHPhysical Uplink Control Channel, SRSSignaling Reference Signal, or PRACHPhysical Random Access Channel when the necessary parameters are defined. For PUSCH, PUCCH, and SRS autodetection, channel parameters include a Sync Slot parameter. There must be a unique sync slot in the channel/signal corresponding to the Sync Type setting in order for the frame boundary to be determined successfully. The signal will still demodulate when there is no unique sync slot, but the time indexes (slot, symbol, etc.) may be incorrect. To configure the demodulator to automatically detect the sync slot, select the Auto Sync parameter for the channel or signal. To specify a sync slot for a channel or signal, make sure the corresponding tab is active, then specify the Channel Parameters or Signal Parameters, and Per-slot Parameters for the sync slot. See the Uplink user allocations topic for instructions on configuring uplink user allocations. |
| RB Auto Detect Mode | Only Power Based RB autodetection is supported in uplink mode. |
| Auto-detect Power Levels | Codeword power level autodetection is only available for downlink signals (when RB Auto Detect Mode is set to Decode PDCCH). |
| Cell ID | Sets the uplink user's physical-layer Cell ID. |
| RNTI | Specifies the user's Radio Network Temporary Identifier. RNTI is required for PUCCH and PUSCH decoding (see the PUCCH Bits and PUSCH Bits parameters). |
| Frame No. | Specifies the frame number to use for data in the Measurement Interval. Frame number is used in the standard by PUCCH frequency hopping type 1 and for SRS. |
| Group Hop | Determines whether group hopping is enabled. Selecting Group Hop disables Seq Hop. |
| Seq Hop | Determines whether sequence hopping is enabled. Selecting Seq Hop disables Group Hop. |
| PUSCH, PUCCH, SRS, PRACH | These are the uplink channels/signals that can be defined for a user. Channel/signal parameters for each user mapping are defined in the respective tabs on the left of the LTE Allocation Editor dialog. The parameters in each tab are described in the following sections in this topic. Click on a link below to navigate to the corresponding channel/signal's section: PUSCH, PUCCH, SRS, PRACH |
| Present in Signal | Selecting the Present in Signal check box for a channel will add the channel to the current user's channel definitions in Composite Include and enable the parameters on the corresponding tab in the LTE Allocation Editor. PRACH analysis is done separately from the other channels and signals. Selecting Present in Signal for PRACH will clear the Present in Signal check boxes for the other channels and signals. |
| Include in Analysis | Selecting the Include in Analysis check box will cause the channel to be shown on applicable traces and included in Error Summary calculations. When Include in Analysis is cleared, only the Frame Summary trace will show information about this user's PUSCH channel. This parameter has the same effect as selecting or clearing check boxes in the Composite Include list of users and channels. |
| Add | Adds a user allocation. |
| Delete | Deletes the selected user allocation. |
| PUSCH | The LTE demodulator can autodetect PUSCH allocations and group them by modulation type. When RB Auto Detect is selected, the demodulator will autodetect PUSCH allocations that match the required parameters. See the RB Auto Detect row (above) in this table for more information about configuring autodetection parameters. Also, see the PUSCH allocations topic for instructions on configuring PUSCH. |
| Channel Parameters | |
| Auto Sync | Auto Sync sets the demodulator to automatically find a sync slot. RB Auto Detect selected:
RB Auto Detect cleared:
|
| Sync Slot | Specifies the index of the slot to use for initial synchronization when PUSCH DM-RSDeModulation Reference Signal (LTE) is selected as the Sync Type. The demodulator searches for the slot with the characteristics specified in Per-slot Parameters, and the slot that matches the Per-slot Parameters with the highest correlation will be assigned the slot number given in the Sync Slot parameter. To specify a sync slot for PUSCH, make sure the PUSCH tab is active, then specify Sync Slot, Channel Parameters, and Per-slot Parameters for the sync slot. |
| Freq. Hopping | Specifies whether frequency hopping has been enabled for the current user. The available selections are the following:
When the number of uplink resource blocks is greater than or equal to 50, all five selections are available. When the number of uplink resource blocks is less than 50, only the Off, Type 1, +1/2, and Type 2 selections are available. When Freq Hopping is set to Off, signals that use frequency hopping can still be demodulated as long as the correct physical resource blocks and mirroring information is provided. See Sections 8.4.1 and 8.4.2 of 3GPP TS 36.213 for more information about hopping bits. |
| Freq. HopMode | Specifies whether the signal undergoes inter-subframe hopping or intra and inter-subframe hopping. Possible selections are Inter-SF and Intra/Inter-SF. This parameter is available only when Freq Hopping is set to a value other than Off. |
| NRBHO1) Hopping Offset (LTE), or 2) Handover: The process in which an mobile station (MSmobile station: A station in the mobile service intended to be used while in motion or during halts at unspecified points. A mobile station (MS) is always a subscriber station (SS) unless specifically excepted otherwise in the standard.) migrates from the air-interface provided by one base station (BS) to the air-interface provided by another base station (BS). Two HO variants are definded: -break-before-make HO: A HO where service with the target BS starts after a disconnection of service with the previous serving BS. - make-before-break HO: A HO where service with the target BS starts before disconnection of the service with the previous serving BS. | Specifies the PUSCH frequency hopping offset in number of resource blocks. See Section 5.3.4 of 3GPP TS 36.211 for more information. |
| NSB | Specifies the number of frequency hopping sub-bands. This is a higher layer parameter. See Section 5.3.4 of 3GPP TS 36.211 for more information. |
| Auto-calculate per-slot params | Selecting this parameter causes DMRS Group, DMRS Seq, and DMRS Cyclic Shift to be set for each slot allocation automatically using the following three parameters. |
| nDMRS(1) | Specifies the value of nDMRS(1) used by the selected user mapping. See Section 5.5.2.1.1 of 3GPP TS 36.211 for more information. |
| nDMRS(2) | Specifies the value of nDMRS(2) used by the selected user mapping. See Section 5.5.2.1.1 of 3GPP TS 36.211 for more information. |
| Dss | Specifies the value of the higher-layer parameter groupAssignmentPUSCH (Dss ) used by the selected user mapping. See Section 5.5.1.3 of 3GPP TS 36.211 for more information. |
| Per-slot Parameters | |
| Couple | Selecting the check box to the right of a parameter will couple that parameter across all PUSCH RB allocation groups. |
PRB Start/VRB Start | Specifies the physical/virtual RB start boundary in frequency. This parameter is specified in virtual resource blocks when Freq. Hopping is enabled and is specified in physical resource blocks when Freq. Hopping is set to Off. |
| PRB End/VRB End | Specifies the physical/virtual RB end boundary in frequency. This parameter is specified in virtual resource blocks when Freq. Hopping is enabled and is specified in physical resource blocks when Freq. Hopping is set to Off. |
| Mod Type | PUSCH modulation type: QPSK, QAM16, or QAM64. |
| Power (dB) | Sets the PUSCH average power level. PUSCH, PUCCH, PUSCH DMdirected mesh: The realizations of a physical mesh using substantially directional antennas. See also: mesh-RS, PUCCH DM-RS, and SRS powers are specified relative to the 0 dB level determined by the power of the channel/signal chosen for synchronization. See Sync Type for more information. |
DMRS Group (u) | Specifies the DMRS Group (u) for a slot. When Auto-calculate per-slot params is selected, this parameter is disabled. When Auto-calculate per-slot params is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
| DMRS Seq (v) | Specifies the DMRS Sequence (v) for a slot. When Auto-calculate per-slot params is selected, this parameter is disabled. When Auto-calculate per-slot params is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
| DMRS Cyclic Shift | Specifies the DMRS Cyclic Shift for a slot. When Auto-calculate per-slot params is selected, this parameter is disabled. When Auto-calculate per-slot params is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
| DMRS Power (dB) | Specifies the average PUSCH DMRS power. PUSCH, PUCCH, PUSCH DM-RS, PUCCH DM-RS, and SRS powers are specified relative to the 0 dB level determined by the power of the channel/signal chosen for synchronization. See Sync Type for more information. |
| Mirroring | Specifies mirroring (fm(i) defined in Section 5.3.4 of 3GPP TS 36.211) when Freq Hopping is set to Off and RB Auto Detect is cleared. Possible values are 0 and 1. Mirroring is autodetected when RB Auto Detect is selected. To analyze signals without frequency hopping or with Type 1 frequency hopping, set Mirroring to 0. To analyze signals with Type 2 frequency hopping, set Mirroring to the appropriate mirroring value. |
| CUR_TXTransmit or transmitter_NB mod 2 | Specifies the value of the higher layer parameter CURRENT_TX_NB, modulo 2. This parameter is only used when RB Auto Detect is cleared, there is one subband (NSB = 1), Freq Hopping is set to a value other than Off, and Freq.HopMode is set to Inter-SF. Possible values for this parameter are 0 or 1. |
| Add | Adds a slot allocation. |
| Delete | Deletes the selected slot allocation. |
| Slot Up | Moves the selected slot allocation up in time (increasing slot number) to the closest available slot allocation for a user. |
| Slot Down | Moves the selected slot allocation down in time (decreasing slot number) to the closest available slot allocation for a user. |
| PUCCH | The LTE demodulator can analyze PUCCH signals. When RB Auto Detect is selected, all PUCCH allocations that match the parameters given in Channel Parameters and Per-slot Parameters will be autodetected. When RB Auto Detect is cleared, PUCCH subframe allocations will need to be defined manually. |
| Channel Parameters | |
| Auto Sync | Auto Sync configures the demodulator to automatically find a sync slot. This parameter does not have any effect when Sync Type is set to a channel/signal other than PUCCH DMRS. RB Auto Detect selected:
PUCCH Format and nPUCCH(1) are expected to be constant for the entire frame unless Auto-detect Format/nPUCCH(1) is selected. RB Auto Detect cleared:
|
| Sync Slot | Specifies the index of the slot to use for initial synchronization when PUCCH DM-RS is selected as the Sync Type. The demodulator searches for the slot with the characteristics specified in Per-slot Parameters, and the slot that matches the Per-slot Parameters with the highest correlation will be assigned the slot number given in the Sync Slot parameter. To specify a sync slot for PUCCH, make sure the PUCCH tab is active, then specify Sync Slot, Channel Parameters, and Per-slot Parameters for the sync slot. |
Auto-calculate | Sets PUCCH Per-slot Parameters First RB, Cyclic Shift, OS, and DMRS Group (u) to be automatically calculated for each slot given the parameters NRB(2), NCS(1) , nPUCCH(1) , nPUCCH(2) , DshiftPUCCH which are defined in 3GPP TS 36.211 Section 5.4. |
NRB(2) | Specifies the number of resource blocks per slot that are available for PUCCH type 2/2a/2b transmissions. NRB(2) is an integer in the range [0, frequency width of frame in units of RB]. |
NCS(1) | Specifies the number of cyclic shifts used for PUCCH formats 1/1a/1b in a resource block with a mix of formats 1/1a/1b and 2/2a/2b. |
nPUCCH(2) | Resource index for PUCCH formats 2/2a/2b. |
DshiftPUCCH | DshiftPUCCH is a higher-layer parameter. |
Auto-detect Format/nPUCCH(1) | Selecting this check box enables autodetection of PUCCH Format and nPUCCH(1) for all subframes. This is useful when the format and/or nPUCCH(1) value is different for each subframe. When this parameter is cleared and RB Auto Detect is selected, PUCCH parameters are autodetected, but PUCCH Format and nPUCCH(1) are expected to be constant for the entire frame. When this parameter is selected, the Auto Sync check box is disabled. When Sync Type is set to PUCCH DMRS, you must define a sync slot by setting the Per-Slot Parameters for the sync slot as well as setting the index using the Sync Slot parameter. |
| Per-slot Parameters | |
| Format | Sets the PUCCH type. When RB Auto Detect is selected, the value selected for the Format parameter is assumed to apply to all allocated slots. |
| Cyclic Shift | Sets PUCCH cyclic shift. When Auto-calculate is selected, this parameter is disabled. When Auto-calculate is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
| OS | Sets the Orthogonal Sequence index for PUCCH. When Auto-calculate is selected, this parameter is disabled. When Auto-calculate is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
Power (dB) | Specifies the average PUCCH DMRS power for a slot. PUSCH, PUCCH, PUSCH DM-RS, PUCCH DM-RS, and SRS powers are specified relative to the 0 dB level determined by the power of the channel/signal chosen for synchronization. See Sync Type for more information. |
| DMRS Group (u) | Sets the group number for the PUCCH demodulation reference signal (DMRS). When Auto-calculate is selected, this parameter is disabled. When Auto-calculate is cleared and RB Auto Detect is selected, the value of this parameter is assumed to apply to all allocated slots. |
| DMRS Power (dB) | Sets the average power level for the PUCCH demodulation reference signal (DMRS) during the selected subframe. PUSCH, PUCCH, PUSCH DM-RS, PUCCH DM-RS, and SRS powers are specified relative to the 0 dB level determined by the power of the channel/signal chosen for synchronization. See Sync Type for more information. |
| nPUCCH(1) | Resource index for PUCCH Types 1/1a/1b. |
| Add | Adds a subframe allocation. |
| Delete | Deletes the selected subframe allocation. |
| Subframe Up | Moves the selected subframe allocation up in time (increasing subframe number) to the closest available subframe allocation for a user. |
| Subframe Down | Moves the selected subframe allocation down in time (decreasing subframe number) to the closest available subframe allocation for a user. |
SRS | For SRS autodetection, the following Signal Parameters need to be specified. Only SRS transmissions that match these parameters will be autodetected. SRS is always autodetected whether or not RB Auto Detect is selected. In calculating the parameter nSRS, nf is always set to zero. The nSRS calculation is listed in Section 5.5.3.2 of 3GPP TS 36.211. |
| Signal Parameters | |
| Auto Sync | Auto Sync sets the demodulator to automatically find a sync slot.
|
| Sync Slot | Specifies the index of the slot to use for initial synchronization when SRS is selected as the Sync Type. The demodulator searches for the slot with the characteristics specified in the Signal Parameters, and the slot that matches the Signal Parameters with the highest correlation will be assigned the slot number given in the Sync Slot parameter. To specify a sync slot for SRS, make sure the SRS tab is active, then specify Sync Slot and Signal Parametersfor the sync slot. |
| Cyclic Shift (nSRSCS) | nSRSCS determines the cyclic shift (a) of SRS from the equation in Section 5.5.3.1 in 3GPP TS 36.211. |
| Power (dB) | Specifies the average power for SRS. PUSCH, PUCCH, PUSCH DM-RS, PUCCH DM-RS, and SRS powers are specified relative to the 0 dB level determined by the power of the channel/signal chosen for synchronization. See Sync Type for more information. |
| SRS Bandwidth(BSRS) | Specifies the SRS bandwidth. This parameter, along with CSRS, determines the values of mSRS,b and Nb from Tables 5.5.3.2-1 through 5.5.3.2-4 in TS 36.211. Possible values for this parameter are in the set {0, 1, 2, 3}. |
| SRS BW Config(CSRS) | Specifies the SRS bandwidth configuration. This parameter, along with BSRS, determines the values of mSRS,b and Nb from Tables 5.5.3.2-1 through 5.5.3.2-4 in TS 36.211. Possible values for this parameter are in the set {0, 1, 2, 3, 4, 5, 6, 7}. |
| SRS Hopping BW(bhop) | Specifies the SRS parameter bhop. This parameter determines whether SRS frequency hopping is enabled. SRS frequency hopping is enabled when bhop < BSRS. The possible values for this parameter are in the set {0, 1, 2, 3}. |
| Tx Comb (kTC) | kTC is the transmissionComb parameter which is specified for the UE by higher layers. This parameter influences the starting frequency location of SRS. See Section 5.5.3.2 in 3GPP TS 36.211 for more information. The possible values for this parameter are in the set {0, 1}. |
| Freq Dom Pos(nRRC) | nRRC is the freqDomainPosition parameter and is specified by higher layers. This parameter is used in calculating nb, the frequency position indexes. See Section 5.5.3.2 in 3GPP TS 36.211 for more information. |
| Subframe Config | Specifies the value for srsSubframeConfiguration in Table 5.5.3.3-1 (FDDFrequency Division Duplex: A duplex scheme in which uplink and downlink transmissions use different frequencies but are typically simultaneous.) or Table 5.5.3.3-2 (TDD) in TS 36.211. srsSubframeConfiguration determines TSFC and DSFC. Possible values are integers in the range [0,15]. |
| Config Index(ISRS) | Specifies the SRS Configuration Index value which determines SRS periodicity and subframe offset configuration from Table 8.2-1 for FDD and Table 8.2-2 for TDD in 3GPP TS 36.213. The possible values for this parameter are the integers in the range [0, 1023]. |
SRSMaxUpPTS (TDD only) | Specifies the upper-layer parameter srsMaxUpPts. This parameter determines whether SRS can occupy all frequency domain positions in the UpPTSUplink Pilot Time Slot (LTE TDD) section of special subframes. When SRSMaxUpPTS = True, all subcarriers are available to be allocated for SRS transmissions. When SRSMaxUpPTS = False, SRS cannot be located in subcarriers reserved for PRACH transmissions. Subcarriers reserved for PRACH transmissions are calculated using the parameters SRS NraS1 and SRS NraS6. See Section 5.5.3.2 of 3GPP TS 36.211 for more information about SRSMaxUpPTS. |
SRS NraS1 (TDD only) | Specifies the number of PRACH preamble allocations in UpPTS during the first special subframe (subframe 1). |
SRS NraS6 (TDD only) | Specifies the number of PRACH preamble allocations in UpPTS during the second special subframe (subframe 6). |
PRACH | The LTE demodulator can detect and demodulate PRACH preamble formats 0-3 given the Channel Parameters listed below. The demodulator auto-detects all PRACH preambles matching the specified PRACH Channel Parameters. For FDD, the first PRACH preamble found is numbered as the lowest subframe corresponding to the specified Configuration Index and subsequent preambles are specified relative to that. For example, if the first PRACH allocation is in subframe 2, the demodulator would assign subframe 2 to the first PRACH preamble found. For TDD, PRACH resources can be multiplexed both in time domain and frequency domain. The exact locations are determined by PRACH Configuration Index and the LTE signal's uplink-downlink configuration. PRACH analysis is performed separately from PUSCH, PUCCH, and SRS. The demodulator assumes that nf, the system frame number, is 0 when performing PRACH analysis. |
| Channel Parameters | |
| NRA1) Random Access, or 2) Receiver AddressPRBoffset | Specifies the index of the first RB available for PRACH transmission in each subframe. This parameter only applies to PRACH formats 0-3 and does not affect the start location of a format 4 preamble. The minimum value is 0, and the maximum value is [number of resource blocks in a slot] - 6. |
| Configuration Index | Specifies the PRACH-Configuration-Index parameter. This parameter determines the PRACH preamble format and the locations where PRACH can be transmitted in the frame. This information is given in Table 5.7.1-2 for frame type 1 FDD signals and in Table 5.7.1-3 for frame type 2 TDD signals in 3GPP TS 36.211. |
| Logical Root Seq Index | Specifies the value of RACH_ROOT_SEQUENCE which is the logical index for the Zadoff-Chu sequence used in generating the PRACH preambles for the cell. For preamble formats 0-3, there are 838 total logical indexes. For preamble format 4, there are 138 logical indexes. The mapping between logical and physical Zadoff-Chu indexes is given in Table 5.7.2-4 for preamble formats 0-3 and in Table 5.7.2-5 for preamble format 4 in TS 36.211. |
| Cyclic Shift Set | Specifies the setting of the higher-layer parameter High-speed-flag, which determines whether the restricted or unrestricted cyclic shift set is used. This parameter, along with the NCS Configuration parameter determine the value of NCS for PRACH preamble formats 0-3. See Table 5.7.2-2 in 3GPP TS 36.211. Possible values for this parameter are Restricted or Unrestricted. |
| NCS Configuration | Specifies the NCS configuration index which, along with Cyclic Shift Set, determines the value of NCS used for PRACH preamble generation for preamble formats 0-3. However, only NCS Configuration is needed to determine the value of NCS for PRACH preamble format 4. NCS values for PRACH preamble formats 0-3 are in Table 5.7.2-2 and NCS values for PRACH preamble format 4 are in Table 5.7.2-3 in TS 36.211. NCS Configuration is an integer between 0 and 15. |
| Preamble Index | Specifies which of the 64 preambles in the cell is being used by the LTE signal being analyzed. There are 64 possible preamble sequences for the cell. The higher-layer parameter RACH_ROOT_SEQUENCE (specified by Logical Root Seq Index) specifies a Zadoff-Chu physical root sequence index from Tables 5.7.2-4 and 5.7.2-5 in 3GPP TS 36.211. Preamble sequences are generated as as cyclic shifts of the Zadoff-Chu (ZC) sequence determined by the physical root sequence index. When there are fewer than 64 cyclic shifts available, the logical sequence index is incremented and the preamble sequences are generated from cyclic shifts of the resulting ZC sequence. This is repeated until all 64 preamble sequences have been generated. See Section 5.7.2 in 3GPP TS 36.211 for more information. Possible values are integers in the range [0, 63]. |
| Power (dB) | Specifies the average power of PRACH subcarriers. |
Sync Resource (TDD only) | Sync Resource is a demodulator-specific parameter that determines which PRACH resource to use for initial synchronization. Table 5.7.1-4 in 3GPP TS 36.211 lists the possible PRACH mappings. PRACH Configuration Index and frame UL/DL configuration determine which of the mappings is used. Certain mappings define multiple PRACH resources. The value of the Sync Resource parameter determines which PRACH resource is used for initial synchronization, with Sync Resource = 0 being the first PRACH resource in the table cell. |
See Also
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LTE Frame Structure
The figure below shows the LTE frame structure under Time division mode (TDD) Type 2 and Frequency Division mode (FDD) Type 1.
Differences in LTE Frame Structure
Main differences in LTE Frame Structure between the two modes are
- Frame 0 and frame 5 (always downlink in TDD)
- Frame 1 and frame 6 is always used as for synchronization in TDD
- Frame allocation for Uplink and Downlink is settable in TDD
The sampling rate in both LTE FDD and LTE TDD is the same and both technologies operate under a 1-ms sub-frame (TTI Transmission Time Interval) and 0.5us timeslot definition.
The first 3 configurations (0-2) for TDD can also be viewed as 5ms allocation due to repetition. The figure below shows a detailed relationship between rates and frame structure in LTE.
LTE Resource Block Architecture
The building block of LTE is a physical resource block (PRB) and all of the allocation of LTE physical resource blocks (PRBs) is handled by a scheduling function at the 3GPP base station (eNodeB).
What is the resource block in LTE?
- One frame is 10ms and it consists of 10 sub-frames
- One LTE subframe is 1ms and contains 2 slots
- One slot is 0.5ms in time domain and each 0.5ms assignment can contain N resource blocks [6 < N < 110] depending on the bandwidth allocation and resource availability.
- One resource block is 0.5ms and contains 12 subcarriers for each OFDM symbol in frequency domain.
- There are 7 symbols (normal cyclic prefix) per time slot in the time domain or 6 symbols in long cyclic prefix for LTE.
Lte Slot Symbols
LTE Resource element is the smallest unit of resource assignment and its relationship to resource block is shown as below from both a timing and frequency perspective.
Reference Signal Structure in lte resource block – What is a resource block what does it consist of?
Reference signal is the “UMTS Pilot” equivalent and it is used by UE in LTE to predict the likely coverage condition on offer for each of the eNodeB cell received. The figure below shows the locations of the reference signal within each sub-frame when transmit antennae are used by the cell.
As LTE is a MIMO based technology so for lte resource block it can have more than two transmit antennae and in order to avoid reference signals from the same cell interfering with each other, different antennae will be transmitting reference signal at different time and frequency and how these are allocated are shown below.
As defined in the standard for LTE TDD operations, the channel-sounding mechanism involves the UE’s transmitting a deterministic signal that can be used by the eNodeB to estimate the UL channel from the UE.
Lte Slot Symbol Image
If the LTE UL and LTE DL channels are properly calibrated, the eNodeB can then use the UL channel as an estimate of the DL channel, due to channel reciprocity thats lte resource block architecture.
What is an LTE frame structure?
Lte Slot Symbol Meaning
In LTE, DL and UL transmissions are organized in radio frames of 10 ms each. Each frame is divided into ten subframes of equal size. The duration of each subframe is 1 ms. In addition, each subframe is further subdivided into two equal time slots, ie each slot is 0.5 ms.