Generate PRACH OFDM information for multiple PRACH slots. The example shows that the actual PRACH slot duration deviates from the nominal duration to ensure that the slot spans the entire active PRACH preambles.
Specify carrier configuration parameters.
Configure PRACH for format 1.
Obtain the nominal PRACH slot duration.
Obtain the starting subframes for the active PRACH preambles from the PRACH configuration tables.
Display the PRACH OFDM information for PRACH slot number 0. The first nominal PRACH slot period, lasting totSubframes
number of subframes, spans subframes 0, 1, and 2. However, according to TS 38.211 Table 6.3.3.2-2, the first active PRACH preamble starts in subframe 1 and ends in subframe 3. To ensure that the PRACH slot spans the whole active preamble, the PRACH slot must contain one additional subframe. Therefore, the value of OffsetLength
is equal to one subframe.
Nfft: 12288
SampleRate: 15360000
CyclicPrefixLengths: [10512 0]
GuardLengths: [0 10992]
SymbolLengths: [22800 23280]
OffsetLength: 15360
Windowing: 430
Display the PRACH OFDM information for PRACH slot number 1. The lengths of the symbol, cyclic prefix, and guard are empty. Therefore, the corresponding waveform lasts zero subframes. In this case, the PRACH slots are balanced with the nominal PRACH slot period. The value of OffsetLength
is zero.
Nfft: 12288
SampleRate: 15360000
CyclicPrefixLengths: [1×0 double]
GuardLengths: [1×0 double]
SymbolLengths: [1×0 double]
OffsetLength: 0
Windowing: 430
Display the PRACH OFDM information for PRACH slot number 2. The first subframe of the PRACH slot is subframe 4 and spans subframes 4, 5, and 6, without the additional subframes. However, according to TS 38.211, the first active PRACH preamble starts in subframe 6 and occupies subframes 6, 7, and 8. To ensure that the PRACH slot spans the whole active preamble, the PRACH slot must contain two additional subframes. Therefore, the value of OffsetLength
is equal to two subframes.
Nfft: 12288
SampleRate: 15360000
CyclicPrefixLengths: [10512 0]
GuardLengths: [0 10992]
SymbolLengths: [22800 23280]
OffsetLength: 30720
Windowing: 430