Distributed MISO OFDM Signal Orthogonality via Symbol Pair Allocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Distributed MISO telecommunications networks face challenges in maintaining signal orthogonality and diversity due to varying propagation conditions between geographically distant transmission entities, preventing effective space-time decoding and limiting network deployment.
Innovation Solution
A method involving the generation and allocation of OFDM signals by multiple transmission entities, using space-time coding and cyclic or selective allocation of symbol pairs to ensure orthogonality and collinearity, allowing for the averaging of propagation channel effects without requiring additional spectral resources or quality information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If distributed MISO networks transmit signal replicas from geographically distant transmission entities, then network deployment flexibility and coverage area are improved, but signal orthogonality and temporal diversity properties are degraded due to varying propagation conditions
Solution Approach 1:
The patent segments the transmission process into distinct phases: space-time encoding at the transmitter, OFDM modulation with cyclic prefix insertion, and separate reception processing for each transmission entity. This segmentation allows each component to be optimized independently, enabling distributed entities to maintain orthogonality despite geographical separation by processing signals through identical structured operations.
Solution Approach 2:
The patent changes the parameter representation from time-domain space-time codes to frequency-domain OFDM signals. By transforming the signal representation and using cyclic prefix insertion to handle propagation delays, the system maintains orthogonality properties across distributed entities with different propagation conditions, resolving the contradiction between deployment flexibility and signal reliability.
2Reliability
If space-time coding is applied to maintain orthogonality between signal and replicas, then signal reception quality is improved, but the system becomes limited to co-located transmission entities and cannot support geographically distributed networks
Solution Approach 1:
The patent creates a universal transmission framework using OFDM that can simultaneously support both co-located and geographically distributed transmission entities. The cyclic prefix structure and frequency-domain processing provide a unified mechanism that maintains orthogonality regardless of entity location, allowing the system to serve multiple network configurations with a single standardized approach.
Solution Approach 2:
The patent introduces OFDM modulation with cyclic prefix as an intermediary layer between the space-time coded signal and the physical transmission channel. This intermediary transforms the time-domain orthogonality requirements into frequency-domain orthogonality that is more robust to propagation delays, enabling geographically distributed entities to maintain signal quality while preserving network configuration flexibility.
3Ease of manufacture
If OFDM signals are transmitted by multiple distributed entities without coordinated allocation, then network deployment is simplified, but spectral resources are wasted and signal quality deteriorates due to lack of orthogonality
Solution Approach 1:
The patent implements periodic cyclic allocation of subcarriers to transmission entities, where each entity is assigned specific subcarriers in a repeating pattern across time-frequency resources. This periodic structure simplifies deployment by providing deterministic resource allocation that requires minimal coordination, while simultaneously improving spectral efficiency by ensuring orthogonal resource usage and preventing interference between distributed entities.
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The invention relates to a method for transmitting a data signal comprising a sequence of symbols intended for a receiver, said method comprising the generation of a plurality of OFDM signals respectively transmitted by a plurality of transmission entities (EEi). The method includes the following steps: ° generating a plurality of a sequence of pairs of symbols, comprising the sub-steps of generating at least one pair of symbols that are orthogonal to an existing pair of symbols of the sequence of symbols, generating at least one pair of symbols by duplicating the existing pair of symbols, and allocating at least one existing pair, at least one orthogonal pair of symbols and at least one duplicated pair of symbols to the transmission entities of the plurality of transmission entities, the sub-steps being repeated for all the pairs of symbols in said sequence of symbols, ° generating the plurality of OFDM signals according to the plurality of a sequence of pairs of symbols, the OFDM signals comprising a number of sub-carriers equal to twice the number of transmitting entities.