Question

以下代码来自IEEE 802.15.6无线体域网标准。通道实现的数量是多少？我该如何选择它的价值？该值与通过通道传输的输入信号长度之间的关系是什么？

function [h, t, n_p] = uwb_hospban_chan_CM4(num_channels, body_direction)
% Function for getting channel realizations for UWB Hospital BAN channel CM4.
% Igor Dotlic (dotlic@nict.go.jp) March 2009.
% Input variables
% num_channels - number of channel realizations
% body_direction= 1: 0 deg, 2: 90 deg, 3: 180 deg, 4: 270 deg
% Output variables
% h - comlex multipath amplitude responses
% t - times of multipath arrivals (ns)
% n_p - number of paths for each channel realization
% Fixed model parameters
L_mean = 400; % mean number of arrival paths
lambda_inv= 0.50125; % mean time between arrivals (ns)
% Model parameters that depend on body direction
if body_direction == 1
Gamma = 44.6346; % (ns)
k_abs = 5.111739;
sigma = 7.30;
elseif body_direction == 2
Gamma = 54.2868; % (ns)
k_abs = 4.348859975;
sigma = 7.08;
elseif body_direction == 3
Gamma = 53.4186; % (ns)
k_abs = 3.638084447;
sigma = 7.03;
elseif body_direction == 4
Gamma = 83.9635; % (ns)
k_abs = 3.983472211;
sigma = 7.19;
end
% Calculating number of paths
n_p = poissrnd(L_mean, 1, num_channels);
for k_chan = 1:num_channels
n_p(k_chan) = max(n_p(k_chan), 1);
end
% Maximum number of paths
n_p_max = max(n_p);
% Allocating memory for channel realizations
h = zeros(n_p_max, num_channels);
t = zeros(n_p_max, num_channels);
% Calculating path arrival times
t_dif = exprnd(lambda_inv, num_channels, n_p_max-1);
for k_chan = 1:num_channels
t(2:n_p(k_chan),k_chan) = cumsum(t_dif(k_chan, 1:n_p(k_chan)-1));
end
% Calculating path levels
for k_chan = 1:num_channels
h(1,k_chan) = exp(i*rand*2*pi)*sqrt(10^(sigma*randn/10));
% Paths 2 onwards
for k_p = 2:n_p(k_chan)
h(k_p, k_chan) = exp(i*rand*2*pi)*...
sqrt(exp(-t(k_p,k_chan)/Gamma-k_abs)*10^(sigma*randn/10));
end
% Normalizing current PDP realization (may be commented out)
h(:,k_chan) = h(:,k_chan)/norm(h(:,k_chan));
end

Answer 1

频道实现的数量是多少？我怎样才能选择它的价值？

看起来这会影响你得到的n_p的大小。很难在不知道你在做什么的情况下建议你想要的价值

该值与通过通道传输的输入信号长度之间的关系是什么？

我认为您的输入信号保持不变，但如果您有多个频道，则会在所有频道上向您发送输入。

IEEE 802.15.6频道

1 个答案: