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Bwp extractor (#22)
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* make test_receiver work with NFFT=9
* add SSB_extractor
* rework test_Decimator_Correlator_PeakDetector_FFT to use SSB_extractor
* simplify FFT_demod more
* update overview diagram
* fix CI name
* remove NFFT dependency from channel_estimator.sv
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@catkira
catkira committed May 26, 2023
1 parent 8376632 commit 7411bf4
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Showing 12 changed files with 239 additions and 147 deletions.
2 changes: 1 addition & 1 deletion .github/workflows/verify.yml
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Expand Up @@ -49,7 +49,7 @@ jobs:
SIM=verilator pytest -v tests/test_receiver.py
SIM=verilator pytest -v tests/test_Decimator_to_SSS_detector.py
- name: Verify with cocotb & icarus
- name: Verify with iVerilog
run: |
pytest -v --workers=10 tests/test_PSS_correlator.py
pytest -v --workers=10 tests/test_PSS_correlator_mr.py
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73 changes: 73 additions & 0 deletions hdl/BWP_extractor.sv
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@@ -0,0 +1,73 @@
module BWP_extractor #(
parameter IN_DW = 16, // input data width
parameter NFFT = 8,
parameter BLK_EXP_LEN = 8,

localparam SFN_MAX = 1023,
localparam SUBFRAMES_PER_FRAME = 20,
localparam SYM_PER_SF = 14,
localparam SFN_WIDTH = $clog2(SFN_MAX),
localparam SUBFRAME_NUMBER_WIDTH = $clog2(SUBFRAMES_PER_FRAME - 1),
localparam SYMBOL_NUMBER_WIDTH = $clog2(SYM_PER_SF - 1),
localparam USER_WIDTH_IN = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN,
localparam USER_WIDTH_OUT = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN + 1
)
(
input clk_i,
input reset_ni,
input wire [IN_DW - 1 : 0] s_axis_in_tdata,
input wire [USER_WIDTH_IN - 1 : 0] s_axis_in_tuser,
input s_axis_in_tlast,
input s_axis_in_tvalid,

output reg [IN_DW - 1 : 0] m_axis_out_tdata,
output reg [USER_WIDTH_OUT - 1 : 0] m_axis_out_tuser,
output reg m_axis_out_tlast,
output reg m_axis_out_tvalid,
output reg PBCH_valid_o,
output reg SSS_valid_o
);

wire [SYMBOL_NUMBER_WIDTH - 1 : 0] sym = s_axis_in_tuser[SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN - 1 -: SYMBOL_NUMBER_WIDTH];
wire [SUBFRAME_NUMBER_WIDTH - 1 : 0] subframe = s_axis_in_tuser[SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN - 1 -: SUBFRAME_NUMBER_WIDTH];
localparam FFT_LEN = 2 ** NFFT;
reg [$clog2(FFT_LEN) - 1 : 0] sc_cnt;
wire is_PBCH_symbol = (sym == 3) && (subframe == 0);
wire is_SSS_symbol = (sym == 4) && (subframe == 0);
localparam SSS_LEN = 127;
localparam SSS_START = FFT_LEN / 2 - (SSS_LEN + 1) / 2;
wire valid_SSS_SC = (sc_cnt >= SSS_START) && (sc_cnt <= SSS_START + SSS_LEN - 1);
localparam PBCH_LEN = 240;
localparam PBCH_START = FFT_LEN / 2 - PBCH_LEN / 2;
wire valid_PBCH_SC = (sc_cnt >= PBCH_START) && (sc_cnt <= PBCH_START + PBCH_LEN - 1);

localparam BWP_LEN = 240;
localparam SC_START = FFT_LEN / 2 - BWP_LEN / 2;
localparam SC_END = SC_START + BWP_LEN;
wire valid_SC = (sc_cnt >= SC_START) && (sc_cnt <= SC_END - 1);

always @(posedge clk_i) begin
if (!reset_ni) begin
m_axis_out_tvalid <= '0;
m_axis_out_tdata <= '0;
m_axis_out_tuser <= '0;
m_axis_out_tlast <= '0;
sc_cnt <= '0;
PBCH_valid_o <= '0;
SSS_valid_o <= '0;
end else begin
SSS_valid_o <= valid_SSS_SC && is_SSS_symbol;
PBCH_valid_o <= valid_PBCH_SC && is_PBCH_symbol;
m_axis_out_tvalid <= valid_SC && s_axis_in_tvalid;
m_axis_out_tdata <= s_axis_in_tdata;
m_axis_out_tuser <= {s_axis_in_tuser, is_PBCH_symbol};
m_axis_out_tlast <= s_axis_in_tvalid && (sc_cnt == (FFT_LEN - 1 - SC_START));

if (s_axis_in_tvalid) begin
if (sc_cnt == FFT_LEN - 1) sc_cnt <= '0;
else sc_cnt <= sc_cnt + 1;
end
end
end

endmodule
28 changes: 27 additions & 1 deletion hdl/Decimator_Correlator_PeakDetector_FFT.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -127,6 +127,12 @@ frame_sync_i
.SSB_start_o(fs_out_SSB_start)
);

localparam BLK_EXP_LEN = 8;
localparam FFT_DEMOD_OUT_USER_WIDTH = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN;
wire [FFT_OUT_DW - 1 : 0] fft_demod_out_tdata;
wire [FFT_DEMOD_OUT_USER_WIDTH - 1 : 0] fft_demod_out_tuser;
wire fft_demod_out_tvalid;
wire fft_demod_out_tlast;
FFT_demod #(
.IN_DW(IN_DW),
.OUT_DW(FFT_OUT_DW),
Expand All @@ -143,10 +149,30 @@ FFT_demod_i(
.s_axis_in_tlast(fs_out_tlast),
.s_axis_in_tuser(fs_out_tuser),
.s_axis_in_tvalid(fs_out_tvalid),
.m_axis_out_tdata(fft_demod_out_tdata),
.m_axis_out_tuser(fft_demod_out_tuser),
.m_axis_out_tlast(fft_demod_out_tlast),
.m_axis_out_tvalid(fft_demod_out_tvalid)
);

BWP_extractor #(
.IN_DW(FFT_OUT_DW),
.NFFT(NFFT),
.BLK_EXP_LEN(BLK_EXP_LEN)
)
BWP_extractor_i(
.clk_i(clk_i),
.reset_ni(reset_ni),

.s_axis_in_tdata(fft_demod_out_tdata),
.s_axis_in_tuser(fft_demod_out_tuser),
.s_axis_in_tvalid(fft_demod_out_tvalid),
.s_axis_in_tlast(fft_demod_out_tlast),

.m_axis_out_tdata(m_axis_out_tdata),
.m_axis_out_tuser(),
.m_axis_out_tlast(),
.m_axis_out_tvalid(m_axis_out_tvalid),
.m_axis_out_tlast(),
.PBCH_valid_o(PBCH_valid_o),
.SSS_valid_o(SSS_valid_o)
);
Expand Down
28 changes: 27 additions & 1 deletion hdl/Decimator_to_SSS_detector.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -124,6 +124,12 @@ frame_sync_i
.SSB_start_o(fs_out_SSB_start)
);

localparam BLK_EXP_LEN = 8;
localparam FFT_DEMOD_OUT_USER_WIDTH = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN;
wire [FFT_OUT_DW - 1 : 0] fft_demod_out_tdata;
wire [FFT_DEMOD_OUT_USER_WIDTH - 1 : 0] fft_demod_out_tuser;
wire fft_demod_out_tvalid;
wire fft_demod_out_tlast;
FFT_demod #(
.IN_DW(IN_DW),
.OUT_DW(FFT_OUT_DW),
Expand All @@ -139,10 +145,30 @@ FFT_demod_i(
.s_axis_in_tlast(fs_out_tlast),
.s_axis_in_tuser(fs_out_tuser),
.s_axis_in_tvalid(fs_out_tvalid),
.m_axis_out_tdata(fft_demod_out_tdata),
.m_axis_out_tuser(fft_demod_out_tuser),
.m_axis_out_tlast(fft_demod_out_tlast),
.m_axis_out_tvalid(fft_demod_out_tvalid)
);

BWP_extractor #(
.IN_DW(FFT_OUT_DW),
.NFFT(NFFT),
.BLK_EXP_LEN(BLK_EXP_LEN)
)
BWP_extractor_i(
.clk_i(clk_i),
.reset_ni(reset_ni),

.s_axis_in_tdata(fft_demod_out_tdata),
.s_axis_in_tuser(fft_demod_out_tuser),
.s_axis_in_tvalid(fft_demod_out_tvalid),
.s_axis_in_tlast(fft_demod_out_tlast),

.m_axis_out_tdata(m_axis_out_tdata),
.m_axis_out_tuser(),
.m_axis_out_tlast(),
.m_axis_out_tvalid(m_axis_out_tvalid),
.m_axis_out_tlast(),
.PBCH_valid_o(PBCH_valid_o),
.SSS_valid_o(SSS_valid_o)
);
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68 changes: 8 additions & 60 deletions hdl/FFT_demod.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ module FFT_demod #(
parameter HALF_CP_ADVANCE = 1,
parameter OUT_DW = 16,
parameter NFFT = 8,
parameter BWP_LEN = 240,
parameter BLK_EXP_LEN = 8,
parameter XSERIES = "OLD", // use "OLD" for Zynq7, "NEW" for MPSoC
parameter USE_TAP_FILE = 0,
Expand All @@ -21,7 +20,7 @@ module FFT_demod #(
localparam SUBFRAME_NUMBER_WIDTH = $clog2(SUBFRAMES_PER_FRAME - 1),
localparam SYMBOL_NUMBER_WIDTH = $clog2(SYM_PER_SF - 1),
localparam USER_WIDTH_IN = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + $clog2(MAX_CP_LEN),
localparam USER_WIDTH_OUT = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN + 1
localparam USER_WIDTH_OUT = SFN_WIDTH + SUBFRAME_NUMBER_WIDTH + SYMBOL_NUMBER_WIDTH + BLK_EXP_LEN
)
(
input clk_i,
Expand All @@ -34,9 +33,7 @@ module FFT_demod #(
output reg [OUT_DW - 1 : 0] m_axis_out_tdata,
output reg [USER_WIDTH_OUT -1 : 0] m_axis_out_tuser,
output reg m_axis_out_tlast,
output reg m_axis_out_tvalid,
output PBCH_valid_o,
output SSS_valid_o
output reg m_axis_out_tvalid
);

// frame information (sfn, subframe number, symbol_number) go into this FIFO because FFT_core does not have tuser
Expand Down Expand Up @@ -142,48 +139,25 @@ end


// This process generates sync signals at the FFT output
// BPW start and end for PDCCH and PDSCH symbols
localparam SC_START = FFT_LEN / 2 - BWP_LEN / 2;
localparam SC_END = SC_START + BWP_LEN;

// BPW start and len for SSS and PBCH symbols
localparam PBCH_LEN = 240;
localparam PBCH_START = FFT_LEN / 2 - PBCH_LEN / 2;

localparam SSS_LEN = 127;
localparam SSS_START = FFT_LEN / 2 - (SSS_LEN + 1) / 2;

reg [$clog2(SYMS_BTWN_SSB) - 1 : 0] current_out_symbol;
reg PBCH_valid;
reg SSS_valid;
reg PBCH_symbol;
reg last_SC;
reg [$clog2(FFT_LEN) - 1 : 0] out_cnt;
reg [USER_WIDTH_OUT - 1 : 0] meta_out;
wire valid_SC = (out_cnt >= SC_START) && (out_cnt <= SC_END - 1);
wire valid_PBCH_SC = (out_cnt >= PBCH_START) && (out_cnt <= PBCH_START + PBCH_LEN - 1);
wire valid_SSS_SC = (out_cnt >= SSS_START) && (out_cnt <= SSS_START + SSS_LEN - 1);
wire fft_val;
reg fft_val_f;
wire [BLK_EXP_LEN - 1 : 0] blk_exp;
wire is_PBCH_symbol = (meta_out_sym == 3) && (meta_out_subframe == 0);
wire is_SSS_symbol = (meta_out_sym == 4) && (meta_out_subframe == 0);
always @(posedge clk_i) begin
if (!reset_ni) begin
out_cnt <= '0;
SSS_valid <= '0;
PBCH_valid <= '0;
// PBCH_symbol <= '0;
current_out_symbol <= '0;
last_SC <= '0;
meta_FIFO_out_ready <= '0;
end else begin
if (fft_val) begin
last_SC <= (out_cnt == (FFT_LEN - 1 - SC_START));

// PBCH_symbol <= (current_out_symbol == 0);
meta_FIFO_out_ready <= out_cnt == (FFT_LEN - 1 - SC_START);
if (meta_FIFO_valid_out) meta_out <= {meta_FIFO_out_data, blk_exp, is_PBCH_symbol};
last_SC <= (out_cnt == FFT_LEN - 1);
meta_FIFO_out_ready <= out_cnt == (FFT_LEN - 2);
if (meta_FIFO_valid_out) meta_out <= {meta_FIFO_out_data, blk_exp};

if (out_cnt == (FFT_LEN - 1)) begin
if (current_out_symbol == SYMS_BTWN_SSB - 1) begin
Expand All @@ -196,12 +170,7 @@ always @(posedge clk_i) begin
end else begin
out_cnt <= out_cnt + 1;
end

PBCH_valid <= valid_SC && is_PBCH_symbol; // only used for debugging
SSS_valid <= valid_SSS_SC && is_SSS_symbol; // only used for debugging
end else begin
PBCH_valid <= '0;
SSS_valid <= '0;
last_SC <= '0;
end
end
Expand Down Expand Up @@ -244,22 +213,14 @@ fft(
// This process corrects 'phase CFO' caused by CP
if (HALF_CP_ADVANCE) begin
localparam MULT_DELAY = 6;
reg [MULT_DELAY - 1 : 0] PBCH_valid_delay;
reg [MULT_DELAY - 1 : 0] SSS_valid_delay;
reg [MULT_DELAY - 1 : 0] last_SC_delay;
// reg [MULT_DELAY - 1 : 0] PBCH_symbol_delay;
reg [USER_WIDTH_OUT - 1 : 0] meta_delay [MULT_DELAY - 1 : 0];

reg [OUT_DW - 1 : 0] coeff [0 : 2**NFFT - 1];
reg [NFFT - 1 : 0] coeff_idx;

reg PBCH_valid_f;
reg SSS_valid_f;
reg last_SC_f;
// reg PBCH_symbol_f;
reg [USER_WIDTH_OUT - 1 : 0] meta_delay_f;
assign PBCH_valid_o = PBCH_valid_f;
assign SSS_valid_o = SSS_valid_f;
assign m_axis_out_tuser = meta_delay_f;
assign m_axis_out_tlast = last_SC_f;

Expand Down Expand Up @@ -320,31 +281,21 @@ if (HALF_CP_ADVANCE) begin
coeff_idx <= '0;
fft_val_f <= '0;
out_data_f <= '0;
PBCH_valid_delay <= '0;
SSS_valid_delay <= '0;
last_SC_delay <= '0;
for (integer i = 0; i < MULT_DELAY; i = i + 1) meta_delay[i] <= '0;
SSS_valid_f <= '0;
PBCH_valid_f <= '0;
last_SC_f <= '0;
// PBCH_symbol_f <= '0;
end else begin
fft_val_f <= fft_val && valid_SC;
fft_val_f <= fft_val;
out_data_f <= {fft_result_im, fft_result_re};
SSS_valid_delay[0] <= SSS_valid;
PBCH_valid_delay[0] <= PBCH_valid;
last_SC_delay[0] <= last_SC;
// PBCH_symbol_delay[0] <= PBCH_symbol;
meta_delay[0] <= meta_out;
for (integer i = 0; i < (MULT_DELAY - 1); i = i + 1) begin
SSS_valid_delay[i+1] <= SSS_valid_delay[i];
PBCH_valid_delay[i+1] <= PBCH_valid_delay[i];
last_SC_delay[i+1] <= last_SC_delay[i];
// PBCH_symbol_delay[i+1] <= PBCH_symbol_delay[i];
meta_delay[i+1] <= meta_delay[i];
end
SSS_valid_f <= SSS_valid_delay[MULT_DELAY - 1];
PBCH_valid_f <= PBCH_valid_delay[MULT_DELAY - 1];
last_SC_f <= last_SC_delay[MULT_DELAY - 1];
// PBCH_symbol_f <= PBCH_symbol_delay[MULT_DELAY - 1];
meta_delay_f <= meta_delay[MULT_DELAY - 1];
Expand All @@ -354,9 +305,6 @@ if (HALF_CP_ADVANCE) begin
end
end
end else begin
assign SSS_valid_o = SSS_valid;
assign PBCH_valid_o = PBCH_valid;

always @(posedge clk_i) begin
if (!reset_ni) begin
m_axis_out_tdata <= '0;
Expand All @@ -365,9 +313,9 @@ end else begin
m_axis_out_tvalid <= '0;
end else begin
m_axis_out_tdata <= {fft_result_im, fft_result_re};
m_axis_out_tlast <= fft_val && (out_cnt == (FFT_LEN - 1 - SC_START));
m_axis_out_tlast <= fft_val && (out_cnt == (FFT_LEN - 1));
m_axis_out_tuser <= meta_out;
m_axis_out_tvalid <= fft_val && valid_SC;
m_axis_out_tvalid <= fft_val;
end
end
end
Expand Down
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