基于QC-LDPC编码的循环移位网络的FPGA实现

一、桶式移位寄存器(barrel shifter) 

基于QC-LDPC编码的循环移位网络的FPGA实现_第1张图片

基于QC-LDPC编码的循环移位网络的FPGA实现_第2张图片

        八位桶式移位寄存器的VHDL实现如下,由于每一层结构相似,于是采用生成语句for_generate实现,使用该代码实现的RTL级分析和理论的结构一致,仿真结果也符合预期。 

entity barrel_shift is
  GENERIC(DATA_WIDTH:   INTEGER:=8;
          CTRL_WIDTH:   INTEGER:=3);
  Port (DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        CTRL:       IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0)
        );
end barrel_shift;

architecture Behavioral of barrel_shift is
SIGNAL LAYER_1_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
SIGNAL LAYER_2_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
SIGNAL LAYER_3_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
begin
    LAYER_1:FOR I IN 0 TO 7 GENERATE
        G1:IF I<=3 GENERATE
            LAYER_1_TEMP(I)<=DATA_IN(I)WHEN CTRL(2)='0'ELSE DATA_IN(I+4);
        END GENERATE G1;
        G2:IF I>3 GENERATE                                              
            LAYER_1_TEMP(I)<=DATA_IN(I)WHEN CTRL(2)='0'ELSE DATA_IN(I-4);
        END GENERATE G2;                                                 
    END GENERATE LAYER_1;
    
    LAYER_2:FOR I IN 0 TO 7 GENERATE
        G3:IF I<=5 GENERATE
            LAYER_2_TEMP(I)<=LAYER_1_TEMP(I)WHEN CTRL(1)='0'ELSE LAYER_1_TEMP(I+2);
        END GENERATE G3;
        G4:IF I>5 GENERATE                                              
            LAYER_2_TEMP(I)<=LAYER_1_TEMP(I)WHEN CTRL(1)='0'ELSE LAYER_1_TEMP(I-6);
        END GENERATE G4;                                                 
    END GENERATE LAYER_2;
    
    LAYER_3:FOR I IN 0 TO 7 GENERATE
        G5:IF I<=6 GENERATE
            LAYER_3_TEMP(I)<=LAYER_2_TEMP(I)WHEN CTRL(0)='0'ELSE LAYER_2_TEMP(I+1);
        END GENERATE G5;
        G6:IF I>6 GENERATE                                              
            LAYER_3_TEMP(I)<=LAYER_2_TEMP(I)WHEN CTRL(0)='0'ELSE LAYER_2_TEMP(I-7);
        END GENERATE G6;                               
    END GENERATE LAYER_3;    
    
    DATA_OUT<=LAYER_3_TEMP;
    
end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第3张图片基于QC-LDPC编码的循环移位网络的FPGA实现_第4张图片

二、QSN网络

基于QC-LDPC编码的循环移位网络的FPGA实现_第5张图片

 2.1LSN网络

基于QC-LDPC编码的循环移位网络的FPGA实现_第6张图片

        该网络的VHDL代码和RTL分析如下 

entity LSN_9x8_network is
  GENERIC(DATA_WIDTH:   INTEGER:=9;
          CTRL_WIDTH:   INTEGER:=4);
  Port (DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        LSN_CTRL:   IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0)
        );
end LSN_9x8_network;

architecture Behavioral of LSN_9x8_network is
SIGNAL LAYER_1_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-9 DOWNTO 0);
SIGNAL LAYER_2_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-5 DOWNTO 0);
SIGNAL LAYER_3_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-3 DOWNTO 0);
SIGNAL LAYER_4_TEMP:    STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
begin
    LAYER_1:FOR I IN 0 TO 0 GENERATE
        G1:IF I=0 GENERATE
            LAYER_1_TEMP(I)<=DATA_IN(I)WHEN LSN_CTRL(3)='0'ELSE DATA_IN(I+8);
        END GENERATE G1;                                       
    END GENERATE LAYER_1;
    
    LAYER_2:FOR I IN 0 TO 4 GENERATE--5
        G2:IF I=0 GENERATE
            LAYER_2_TEMP(I)<=LAYER_1_TEMP(I)WHEN LSN_CTRL(2)='0'ELSE DATA_IN(I+4);
        END GENERATE G2; 
        G3:IF I>0 GENERATE
            LAYER_2_TEMP(I)<=DATA_IN(I)     WHEN LSN_CTRL(2)='0'ELSE DATA_IN(I+4);
        END GENERATE G3;                                               
    END GENERATE LAYER_2;
    
    LAYER_3:FOR I IN 0 TO 6 GENERATE--7
        G4:IF I<=2 GENERATE
            LAYER_3_TEMP(I)<=LAYER_2_TEMP(I)WHEN LSN_CTRL(1)='0'ELSE LAYER_2_TEMP(I+2);
        END GENERATE G4; 
        G5:IF I>2 AND I<=4 GENERATE
            LAYER_3_TEMP(I)<=LAYER_2_TEMP(I)WHEN LSN_CTRL(1)='0'ELSE DATA_IN(I+2);
        END GENERATE G5;
        G6:IF I>4 GENERATE
            LAYER_3_TEMP(I)<=DATA_IN(I)     WHEN LSN_CTRL(0)='0'ELSE DATA_IN(I+2);
        END GENERATE G6;                 
    END GENERATE LAYER_3;    
    
    LAYER_4:FOR I IN 0 TO 7 GENERATE---8
        G7:IF I<=5 GENERATE
            LAYER_4_TEMP(I)<=LAYER_3_TEMP(I)WHEN LSN_CTRL(0)='0'ELSE LAYER_3_TEMP(I+1);
        END GENERATE G7; 
        G8:IF I=6 GENERATE
            LAYER_4_TEMP(I)<=LAYER_3_TEMP(I)WHEN LSN_CTRL(0)='0'ELSE DATA_IN(I+1);
        END GENERATE G8;
        G9:IF I>6 GENERATE
            LAYER_4_TEMP(I)<=DATA_IN(I)     WHEN LSN_CTRL(0)='0'ELSE DATA_IN(I+1);
        END GENERATE G9;                         
    END GENERATE LAYER_4; 
    
    DATA_OUT<=LAYER_4_TEMP(DATA_WIDTH-2 DOWNTO 0);
    
end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第7张图片

 2.2RSN网络 

基于QC-LDPC编码的循环移位网络的FPGA实现_第8张图片

基于QC-LDPC编码的循环移位网络的FPGA实现_第9张图片

 9x9的右移网络的VHDL实现和RTL分析如下

entity RSN_9x9_network is
  GENERIC(DATA_WIDTH:   INTEGER:=9;
          CTRL_WIDTH:   INTEGER:=4);
  Port (DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        RSN_CTRL:   IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0)
        );
end RSN_9x9_network;

architecture Behavioral of RSN_9x9_network is
    COMPONENT LSN_9x8_network IS
       GENERIC(DATA_WIDTH:   INTEGER:=9;
               CTRL_WIDTH:   INTEGER:=4);
        Port (
        DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        LSN_CTRL:   IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0)
        );
    END COMPONENT;
begin
   LSN_9X8:LSN_9x8_network
    GENERIC MAP(
    DATA_WIDTH  =>  DATA_WIDTH,
    CTRL_WIDTH  =>  CTRL_WIDTH
    )
    PORT MAP(   
    DATA_IN(0)  =>  DATA_IN(8),
    DATA_IN(1)  =>  DATA_IN(7),
    DATA_IN(2)  =>  DATA_IN(6),
    DATA_IN(3)  =>  DATA_IN(5),
    DATA_IN(4)  =>  DATA_IN(4),
    DATA_IN(5)  =>  DATA_IN(3),
    DATA_IN(6)  =>  DATA_IN(2),
    DATA_IN(7)  =>  DATA_IN(1), 
    DATA_IN(8)  =>  DATA_IN(0),   
    LSN_CTRL    =>  RSN_CTRL,
    DATA_OUT(0) =>  DATA_OUT(8),
    DATA_OUT(1) =>  DATA_OUT(7),
    DATA_OUT(2) =>  DATA_OUT(6),
    DATA_OUT(3) =>  DATA_OUT(5),
    DATA_OUT(4) =>  DATA_OUT(4),
    DATA_OUT(5) =>  DATA_OUT(3),
    DATA_OUT(6) =>  DATA_OUT(2),
    DATA_OUT(7) =>  DATA_OUT(1)
    );              
    DATA_OUT(0) <=  DATA_IN(0);
end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第10张图片

  2.3MN网络

基于QC-LDPC编码的循环移位网络的FPGA实现_第11张图片

entity MN_9x9_network is
  GENERIC(DATA_WIDTH:   INTEGER:=9);
  Port (LSN_DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        RSN_DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        M_CTRL:         IN  STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        DATA_OUT:       OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0)
        );
end MN_9x9_network;

architecture Behavioral of MN_9x9_network is
begin
    G1:FOR I IN 0 TO DATA_WIDTH-2 GENERATE
        DATA_OUT(I)<=RSN_DATA_IN(I) WHEN M_CTRL(I)='0' ELSE LSN_DATA_IN(I);
    END GENERATE G1;
    DATA_OUT(8)<='0' WHEN FALSE ELSE RSN_DATA_IN(8);
end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第12张图片

 2.4控制模块 

基于QC-LDPC编码的循环移位网络的FPGA实现_第13张图片

 控制模块的VHDL实现和仿真波形图如下

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity CTRL is
  GENERIC(DATA_WIDTH:   INTEGER:=9;
          CTRL_WIDTH:   INTEGER:=4);
  Port (CLK:        IN  STD_LOGIC;
        RST_N:      IN  STD_LOGIC;
        EN:         IN  STD_LOGIC;
        SHIFT_NUM:  IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        M:          OUT STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        LSN_SHIFT:  OUT STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        RSN_SHIFT:  OUT STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0); 
        VALID:      OUT STD_LOGIC  
        );
end CTRL;

architecture Behavioral of CTRL is

begin
    LSN_SHIFT_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN
            LSN_SHIFT<=(OTHERS=>'0');
        ELSIF RISING_EDGE(CLK) THEN
            IF EN='1'THEN
                LSN_SHIFT<=SHIFT_NUM;
            END IF;
        END IF;
    END PROCESS;
    
    RSN_SHIFT_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN
            RSN_SHIFT<=(OTHERS=>'0');
        ELSIF RISING_EDGE(CLK) THEN
            IF EN='1'THEN
                RSN_SHIFT<=9-SHIFT_NUM;
            END IF;
        END IF;
    END PROCESS;
    
    M_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN
            M<=(OTHERS=>'0');
        ELSIF RISING_EDGE(CLK) THEN
            IF EN='1'THEN
                IF SHIFT_NUM>=9 THEN M(0)<='0';ELSE M(0)<='1';END IF;
                IF SHIFT_NUM>=8 THEN M(1)<='0';ELSE M(1)<='1';END IF;
                IF SHIFT_NUM>=7 THEN M(2)<='0';ELSE M(2)<='1';END IF;
                IF SHIFT_NUM>=6 THEN M(3)<='0';ELSE M(3)<='1';END IF;
                IF SHIFT_NUM>=5 THEN M(4)<='0';ELSE M(4)<='1';END IF;
                IF SHIFT_NUM>=4 THEN M(5)<='0';ELSE M(5)<='1';END IF;
                IF SHIFT_NUM>=3 THEN M(6)<='0';ELSE M(6)<='1';END IF;
                IF SHIFT_NUM>=2 THEN M(7)<='0';ELSE M(7)<='1';END IF;
            END IF;
        END IF;
    END PROCESS;
    
    VALID_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN                 
            VALID<='0';            
        ELSIF RISING_EDGE(CLK) THEN      
            IF EN='1'THEN
                VALID<='1';       
            ELSE
                VALID<='0';       
            END IF;
        END IF;
    END PROCESS;
end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第14张图片  2.5顶层

        顶层的作用是将子模块例化,VHDL实现和RTL分析如下

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity QSN_9x9_network is
  GENERIC(DATA_WIDTH:   INTEGER:=9;
          CTRL_WIDTH:   INTEGER:=4);
  Port (CLK:        IN  STD_LOGIC;
        RST_N:      IN  STD_LOGIC;
        EN:         IN  STD_LOGIC;
        SHIFT_NUM:  IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        VALID:      OUT STD_LOGIC
        );
end QSN_9x9_network;

architecture Behavioral of QSN_9x9_network is
    COMPONENT LSN_9x8_network IS
       GENERIC(DATA_WIDTH:   INTEGER:=9;
               CTRL_WIDTH:   INTEGER:=4);
        Port (
        DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        LSN_CTRL:   IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0)
        );
    END COMPONENT;
    
    COMPONENT RSN_9x9_network IS
       GENERIC(DATA_WIDTH:   INTEGER:=9;
               CTRL_WIDTH:   INTEGER:=4);
        Port (
        DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        RSN_CTRL:   IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        DATA_OUT:   OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0)
        );
    END COMPONENT;
    
    COMPONENT MN_9x9_network IS
       GENERIC(DATA_WIDTH:   INTEGER:=9);
        Port (
        LSN_DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        RSN_DATA_IN:    IN  STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
        M_CTRL:         IN  STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        DATA_OUT:       OUT STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0)
        );
    END COMPONENT;
    
    COMPONENT CTRL IS
        GENERIC(DATA_WIDTH:   INTEGER:=9;
                CTRL_WIDTH:   INTEGER:=4);
        Port (
        CLK:        IN  STD_LOGIC;
        RST_N:      IN  STD_LOGIC;
        EN:         IN  STD_LOGIC;
        SHIFT_NUM:  IN  STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        M:          OUT STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
        LSN_SHIFT:  OUT STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
        RSN_SHIFT:  OUT STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0); 
        VALID:      OUT STD_LOGIC  
        );
    END COMPONENT;
--CTRL
SIGNAL M_CTRL:      STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
SIGNAL LSN_SHIFT:   STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
SIGNAL RSN_SHIFT:   STD_LOGIC_VECTOR(CTRL_WIDTH-1 DOWNTO 0);
SIGNAL CTRL_EN:     STD_LOGIC;
--LSN
SIGNAL LSN_OUT:     STD_LOGIC_VECTOR(DATA_WIDTH-2 DOWNTO 0);
--RSN
SIGNAL RSN_OUT:     STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
--MN_OUT
SIGNAL OUT_REG:     STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
SIGNAL DATA_OUT_REG:STD_LOGIC_VECTOR(DATA_WIDTH-1 DOWNTO 0);
--VALID_REG
SIGNAL VALID_REG:   STD_LOGIC;
begin
    CTRL_GE:CTRL
    GENERIC MAP(
    DATA_WIDTH =>   DATA_WIDTH,
    CTRL_WIDTH =>   CTRL_WIDTH
    )
    PORT MAP(
    CLK        =>   CLK,
    RST_N      =>   RST_N,
    EN         =>   EN,
    SHIFT_NUM  =>   SHIFT_NUM,
    M          =>   M_CTRL,
    LSN_SHIFT  =>   LSN_SHIFT,
    RSN_SHIFT  =>   RSN_SHIFT,
    VALID      =>   CTRL_EN
    );
    
    LSN:LSN_9x8_network
    GENERIC MAP(
    DATA_WIDTH =>   DATA_WIDTH,
    CTRL_WIDTH =>   CTRL_WIDTH
    )
    PORT MAP(
    DATA_IN    =>   DATA_IN,  
    LSN_CTRL   =>   LSN_SHIFT,
    DATA_OUT   =>   LSN_OUT
    );
    
    RSN:RSN_9x9_network
    GENERIC MAP(
    DATA_WIDTH =>   DATA_WIDTH,
    CTRL_WIDTH =>   CTRL_WIDTH
    )
    PORT MAP(
    DATA_IN    =>   DATA_IN,  
    RSN_CTRL   =>   RSN_SHIFT,
    DATA_OUT   =>   RSN_OUT
    );
    
    MN:MN_9x9_network
    GENERIC MAP(
    DATA_WIDTH =>   DATA_WIDTH
    )
    PORT MAP(  
    LSN_DATA_IN=>   LSN_OUT,
    RSN_DATA_IN=>   RSN_OUT,
    M_CTRL     =>   M_CTRL,
    DATA_OUT   =>   OUT_REG
    );
    
    OUT_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN
            DATA_OUT_REG<=(OTHERS=>'0');
        ELSIF RISING_EDGE(CLK)THEN
            IF CTRL_EN='1'THEN
                DATA_OUT_REG<=OUT_REG;
            END IF;
        END IF;
    END PROCESS;
    
    DATA_OUT<=DATA_OUT_REG;
    
    VALID_REG_GE:PROCESS(CLK,RST_N)
    BEGIN
        IF RST_N='0'THEN
            VALID_REG<='0';
        ELSIF RISING_EDGE(CLK)THEN
            IF CTRL_EN='1'THEN
                VALID_REG<='1';
            ELSE
                VALID_REG<='0';
            END IF;
        END IF;
    END PROCESS;
    
    VALID<=VALID_REG;

end Behavioral;

基于QC-LDPC编码的循环移位网络的FPGA实现_第15张图片

        使用时钟CLK和复位信号RST_N控制时序,并加入输入输出使能信号。最后实现的结果如下,可以看到左循环移位1~9的结果均正确。 

基于QC-LDPC编码的循环移位网络的FPGA实现_第16张图片

基于QC-LDPC编码的循环移位网络的FPGA实现_第17张图片

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