Random phase modulation method depending on communication distance

A random phase modulation method depending on a communication distance, comprising the following steps:

• step 1:
• performing time synchronization on a transmitter and a receiver, wherein the transmitter is configured to process and send an original signal, and the receiver is configured to recover a received signal;
• step 2:
• according to a sampling rate Ts agreed in advance, obtaining, by the transmitter and the receiver, a kth sampling time:
• tk=t0+kTs
• wherein t0 represents an initial sampling time;
• step 3:
• generating, by the transmitter, a local random signal θ(t0) at the initial sampling time at the initial sampling time t0, wherein θ(t0) has a uniform distribution in an interval [0,2π);
• generating, by the transmitter, a local random signal θ(tk) at a kth sampling time according to a local random signal θ(tk−1) at a previous sampling time, wherein a generation method is as follows:
• θ(tk)=ρθ(tk−1)+√{square root over (1−ρ2)}χ(tk)
• wherein ρ is a constant on an interval [0,1], χ(tk) is a local random signal increment generated by the transmitter at the kth sampling time, and χ(tk) has a uniform distribution in the interval [0,2π);
• step 4:
• calculating, by the transmitter, a sampling point offset
• Δ
• ⁢
• τ
• =
• ⌈
• Δ
• ⁢
• t
• T
• s
• ⌉
• between the transmitter and the receiver according to a transmission delay Δt of the receiver, wherein represents a round-up operation;
• generating, by the transmitter, a precoding signal at the kth sampling time according to a local random signal θ(tk+Δτ) at a k+Δτth sampling time;
• step 5:
• multiplying, by the transmitter, an original signal sk at the kth sampling time with the precoding signal αk the kth sampling time to obtain a transmitting signal xk=skαk at the kth sampling time, and sending the transmitting signal to the receiver, wherein the original signal sk represents a data signal to be sent;
• and
• step 6:
• estimating, by the receiver, the transmitting signal at the kth sampling time to obtain a received signal rk at the kth sampling time, generating, by the receiver, a local matched signal βk=e−jθ(tk) at the kth sampling time according to the local random signal θ(tk) at the kth sampling time, and multiplying, by the receiver, the received signal rk at the kth sampling time with the local matched signal βk at the kth sampling time to obtain an estimation ŝk of the original signal at the kth sampling time.