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long preamble detection method update: cross-correlation inter-peak gap distance -> 1st peak detection

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mmehari 2022-01-04 22:07:54 +01:00
parent aaa8ef3ce5
commit f3e95eaa92
1 changed files with 16 additions and 49 deletions
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65
verilog/sync_long.v
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@ -20,7 +20,7 @@ module sync_long (
output reg [15:0] num_ofdm_symbol,
output reg signed [31:0] phase_offset_taken,
output reg [2:0] state
output reg [1:0] state
);
`include "common_params.v"
@ -122,9 +122,6 @@ complex_to_mag #(.DATA_WIDTH(32)) sum_mag_inst (
reg [31:0] metric_max1;
reg [(IN_BUF_LEN_SHIFT-1):0] addr1;
reg [31:0] metric_max2;
reg [(IN_BUF_LEN_SHIFT-1):0] addr2;
reg [15:0] gap;
reg [31:0] cross_corr_buf[0:15];
@ -169,9 +166,8 @@ stage_mult stage_mult_inst (
localparam S_SKIPPING = 0;
localparam S_WAIT_FOR_FIRST_PEAK = 1;
localparam S_WAIT_FOR_SECOND_PEAK = 2;
localparam S_IDLE = 3;
localparam S_FFT = 4;
localparam S_IDLE = 2;
localparam S_FFT = 3;
reg fft_start;
//wire fft_start_delayed;
@ -324,52 +320,26 @@ always @(posedge clock) begin
end
if (num_sample >= 64) begin
long_preamble_detected <= 1;
num_sample <= 0;
addr2 <= 0;
state <= S_WAIT_FOR_SECOND_PEAK;
mult_strobe <= 0;
sum_stb <= 0;
// offset it by the length of cross correlation buffer
// size
in_raddr <= addr1 - 16;
num_input_consumed <= addr1 - 16;
in_offset <= 0;
num_ofdm_symbol <= 0;
phase_correction <= 0;
next_phase_correction <= phase_offset;
phase_offset_taken <= phase_offset;
state <= S_FFT;
end else if (metric_stb) begin
num_sample <= num_sample + 1;
end
end
S_WAIT_FOR_SECOND_PEAK: begin
do_mult();
if (metric_stb && (metric > metric_max2)) begin
metric_max2 <= metric;
addr2 <= in_raddr - 1;
end
gap <= addr2 - addr1;
if (num_sample >= 64) begin
`ifdef DEBUG_PRINT
$display("PEAK GAP: %d (%d - %d)", gap, addr2, addr1);
$display("PHASE OFFSET: %d", phase_offset);
`endif
if (gap > 62 && gap < 66) begin
long_preamble_detected <= 1;
num_sample <= 0;
mult_strobe <= 0;
sum_stb <= 0;
// offset it by the length of cross correlation buffer
// size
in_raddr <= addr1 - 16;
num_input_consumed <= addr1 - 16;
in_offset <= 0;
num_ofdm_symbol <= 0;
phase_correction <= 0;
next_phase_correction <= phase_offset;
phase_offset_taken <= phase_offset;
state <= S_FFT;
end else begin
state <= S_IDLE;
end
end else if (metric_stb) begin
num_sample <= num_sample + 1;
end
end
S_FFT: begin
if (long_preamble_detected) begin
`ifdef DEBUG_PRINT
@ -553,7 +523,6 @@ end
endtask
task do_clear; begin
gap <= 0;
in_waddr <= 0;
in_raddr <= 0;
@ -575,8 +544,6 @@ task do_clear; begin
metric_max1 <= 0;
addr1 <= 0;
metric_max2 <= 0;
addr2 <= 0;
mult_stage <= 0;