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. Fundamental time unit for most LTE processing, like scheduling. Each subframe consists of two slots (illustrated in Figure 11), which are each 0.5 ms long. Each slot consists of 7 (or 6) symbols. Which is the reference time for defining any slot in LTE and also called as book keeping time. Type 1 radio frame has a duration 10 ms and consists of equally sized 20 slots each of 0.5 ms. A subframe comprises two slots, thus one radio frame has 10 sub‐frames. There are six time units: frame, half-frame, subframe, slot, symbol, and the basic time unit (Ts): Time Unit Value. For regular cases there are 7 OFDM symbols in a 500 μs. Slot the CP lasts 4.7 μs. So that 7(66.7+4.7)=500 μs. Which can absorb a path differential of 4.7.0.3=1.4 km time of flight! The long (extended) CP lasts 16.7 μs. So that 6(66.7+16.7)=500 μs. This CP can absorb 16.7.0.3=5 km of flight time and is used only for very large cells. The symbol 3(the fourth% symbol in LTE UL slot is special. It is special symbol carrying PUSCH DMRS data, it does% not carry any user data.
LTE_DL_DemuxSlot (Downlink Slot De-multiplexer)
Description: Downlink Slot De-multiplexer for LTE DL receiverLibrary: LTE, Multiplex
Parameters
Name | Description | Default | Type |
|---|---|---|---|
Bandwidth | bandwidth: BW 1.4 MHz, BW 3 MHz, BW 5 MHz, BW 10 MHz, BW 15 MHz, BW 20 MHz Casino blue heidelberg. | BW 5 MHz | enum |
NumRxAnts | number of Rx Antennas: Rx1, Rx2, Rx4 | Rx1 | enum |
OversamplingOption | Ratio 1, Ratio 2, Ratio 4, Ratio 8: Ratio 1, Ratio 2, Ratio 4, Ratio 8 | Ratio 2 | enum |
CyclicPrefix | type of cyclic prefix: Normal, Extended | Normal | enum |
Sym_StartPos | start position (without oversampling) to get the OFDM symbol for FFT operation for long CP and short CP symbols respectively, compared to the start position of the OFDM body after CP | {-3,-3} | int array |
Lte Slot Symbol Image
Pin Inputs
Name | Description | Signal Type | |
|---|---|---|---|
1 | FrameData | input downlink frame symbol | multiple complex |
Pin Outputs
Pin | Name | Description | Signal Type |
|---|---|---|---|
2 | OFDMSig | OFDM signal | multiple complex |
Lte Subframe Symbol
Notes/Equations
- This model is used to demultiplex 3GPP LTE downlink slot.
- Each 10 ms radio frame consists of 20 slots of length, numbered from 0 to 19. Each 0.5 ms slot consists of 7 OFDM symbols for normal cyclic prefix or 6 OFDM symbols for extended cyclic prefix.
The cyclic prefix of each OFDM symbol is removed in this model. For normal cyclic prefix, the first OFDM symbol within a slot has different cyclic prefix lengths from other 6 OFDM symbols. For extended cyclic prefix, the 6 OFDM symbols have same cyclic prefix lengths. - The start of each output OFDM symbol is illustrated in the following figure.
- Sym_StartPos is an array of two elements, indicating the start position (without oversampling) of the first output OFDM symbol and other output OFDM symbols in each slot respectively. Here the 'start position' is compared to the first sample of the input OFDM symbol body excluding the cyclic prefix. Hence the value is negative indicating the start position locates in the CP duration of the input symbol as shown in the figure.
Lte Slot Symbol Png
References
Lte Slot Symbols
- 3GPP TS 36.211 v8.4.0, 'Physical Channels and Modulation', Sept 2008.
- 3GPP TS 36.104 v8.3.0 'Base Station (BS) radio transmission and reception', Sept 2008.
- TR 25.814 'Physical layer aspects for evolved Universal Terrestrial Radio Access (UTRA),', V7.0.0, June 2006.
