Biorthogonal bipolar binary shift pulse keying modulation and demodulation method

Abstract

The invention provides a biorthogonal bipolar binary shift pulse keying modulation and demodulation method. According to the method, on the basis of a bipolar binary shift pulse keying modulation and demodulation method, a quaternary symbol sequence is converted to two paths of binary message sequences in a series-to-parallel mode, and bipolar BSK pulse modulation with the same modulation parameter is conducted on a branch I and a branch Q; the modulated carrier waves are mutually orthogonal, namely the phase difference is 90 degrees, the modulation ranges are staggered, namely the two paths of pulse modulation are conducted within the start range and the end range of each binary symbol period respectively, the spectral efficiency is greatly multiplied, the transmission isolation between the branch I and the branch Q is greatly improved, and the strict orthogonality requirement of coherent carrier extraction is substantially lowered; a dual matched filtering method of shock filter multiplied by coherent carrier waves-low-pass filtering or band-pass filtering-related demodulation is adopted for demodulation, the method has dual filtering and noise reduction interference dispelling performance and dual symbol energy maximization effects, and the reliable transmission of biorthogonal modulating signals is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of high-efficiency digital information transmission, relates to information modulation and demodulation in digital communication, and in particular to a dual-orthogonal bipolar binary offset pulse keying modulation and demodulation method. Background technique [0002] 1. Bipolar binary offset pulse keying modulation [0003] In order to improve the traditional binary (binary) amplitude shift keying (2ASK), frequency shift keying (2FSK) and phase shift keying (2PSK, also denoted as BPSK) and other binary shift keying (BSK: Binary Shift Keying ), increasing their guard intervals to prevent multipath channels and intersymbol interference, we have first worked in "Unified Orthogonal Binary Offset-Kind Modulation and Demodulation Method" (Patent No.: ZL200710025203.6) A large class of "Unified Binary Shift Keying" (UBSK: Unified BSK) modulation is proposed, which is defined as follows: [0004] the s 0 (t) = ...

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Problems solved by technology

But the key lies in the strict orthogonality of the two coherent carriers. Once it is not fully satisfied, either way will cause serious interference to the other way, and the extracted coherent carrier will inevitably appear not strictly in the same frequency and phase as the current received signal. It will further reduce and deteriorate the isolation between the I and Q branches, forcing ABSK modulation or bipolar BSK pulse modulation to ensure the carrier synchronization accuracy of the receiving system and the correctness of the I and Q branches to a high standard during orthogonal transmission. Interaction, which virtually increases the complexity and cost of the receiver

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