OFDM Data Allocation for Single-Branch Receiver ICI Elimination
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Solution Overview
Problem
Dual branch orthogonal frequency division multiplexing receivers face in-phase/quadrature-phase imbalance and inter-carrier interference (ICI) when using a single branch receiver, which affects data transmission efficiency.
Innovation Solution
The method involves allocating data streams to sub-carriers in a way that sets certain sub-carriers as null or conjugate values, preventing ICI by using a single branch receiver with either the in-phase or quadrature-phase path, and performing data allocation and processing to eliminate interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual branch receiver with both in-phase and quadrature-phase paths is used, then signal reception capability is improved, but hardware cost and device complexity increase
Solution Approach 1:
The patent extracts only the necessary path (in-phase or quadrature-phase) from the dual branch receiver structure, eliminating the redundant path while maintaining signal reception capability through specific data allocation methods on sub-carriers
Solution Approach 2:
The patent uses data copying and conjugate allocation strategies where data on one path is replicated or conjugated on corresponding sub-carriers, allowing single path reception to achieve performance comparable to dual path receivers
2Device complexity
If a single branch receiver is used to reduce hardware cost, then device complexity is reduced, but in-phase/quadrature-phase imbalance and inter-carrier interference occur
Solution Approach 1:
The patent applies preliminary anti-action by pre-allocation of null sub-carriers and conjugate sub-carriers before signal reception, which prevents inter-carrier interference from occurring in the first place rather than attempting to correct it afterward
Solution Approach 2:
The patent changes the parameter allocation on sub-carriers (using null values and conjugate values strategically) to compensate for the absence of the second path, maintaining signal quality despite using only a single branch receiver
3Productivity
If data is allocated on all sub-carriers to maximize transmission efficiency, then productivity is improved, but inter-carrier interference increases in single branch reception
Solution Approach 1:
The patent segments the sub-carrier spectrum into different functional regions (data sub-carriers, null sub-carriers, conjugate sub-carriers), allocating data only to specific segments while leaving other segments for interference prevention, thereby maintaining transmission efficiency without ICI
Solution Approach 2:
The patent converts the potential harm of unused sub-carriers into a benefit by using them as null or conjugate sub-carriers that actively prevent inter-carrier interference, transforming what would be wasted resources into protective elements
Data Source
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AI summary
Methods of data allocation and signal receiving, a wireless transmitting apparatus, and a wireless receiving apparatus are provided based on orthogonal frequency division multiplexing (OFDM) technology. The wireless transmitting apparatus obtains a data stream and allocates the data stream to a first sub-carrier set. Each of the first sub-carrier set and a second sub-carrier set has sub-carriers with opposite frequencies to each other, respectively. The second sub-carrier is emptied or allocated according the data stream allocated to the first sub-carrier set. The data stream is converted into an OFDM signal transmitted through a transmitting module. The wireless receiving apparatus includes a single branch receiver for receiving a radio frequency (RF) signal and outputting a baseband signal. Subsequently, the data stream is restored from the baseband signal.