OFDM Base Station Frame Pattern Pilot Allocation
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Solution Overview
Problem
In wireless communication systems using OFDM, high-speed terminal movement leads to decreased channel estimation precision and communication quality due to the long interval between pilot symbols, resulting in reduced throughput and transmission speed, especially when the number of pilot symbols is increased to compensate for poor propagation environments.
Innovation Solution
A wireless communication method that uses a fixed frame pattern with varying numbers of common pilots, assigning frames with a large number of pilots to high-speed terminals and frames with fewer pilots to low-speed terminals, allowing for accurate measurement of receiving quality and channel estimation while maintaining data transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pilot symbols is increased to compensate for poor propagation environments, then channel estimation precision improves, but data transmission speed decreases
Solution Approach 1:
The patent segments the frame structure into multiple types (first frame with fewer pilots, second frame with more pilots) and assigns different segments to different terminal groups based on their movement characteristics. This allows each segment to be optimized independently for its specific use case.
Solution Approach 2:
The patent implements dynamic frame assignment where terminals are adaptively assigned to different frame types based on their movement speed and channel conditions. High-speed terminals receive frames with more pilots for better channel estimation, while low-speed terminals receive frames with fewer pilots for higher data throughput.
2Productivity
If the interval between pilot symbols is long, then data transmission efficiency improves, but channel estimation precision deteriorates for high-speed terminals
Solution Approach 1:
The patent applies local quality by configuring different pilot densities in different frame types according to specific terminal requirements. Frames designated for high-speed terminals contain more pilots with shorter intervals, while frames for low-speed terminals have fewer pilots with longer intervals, optimizing each local context.
Solution Approach 2:
The patent changes the pilot symbol parameters (number of pilots, interval between pilots) based on terminal movement characteristics. By switching between different frame configurations, the system dynamically adjusts pilot density to match channel variation rates caused by terminal mobility.
3Reliability
If frames with more pilots are assigned to high-speed terminals, then communication quality improves, but overall base station throughput decreases
Solution Approach 1:
The patent creates a universal frame structure system that serves multiple terminal types simultaneously. The base station transmits both first frame types (optimized for low-speed terminals) and second frame types (optimized for high-speed terminals), allowing a single system to universally accommodate diverse terminal requirements without sacrificing overall throughput.
Solution Approach 2:
The patent applies partial action by providing enhanced pilot sequences (more pilots) only to the extent necessary for high-speed terminals, rather than uniformly increasing pilot density for all terminals. This partial enhancement maintains communication quality for mobile terminals while preserving data transmission efficiency for stationary or low-speed terminals.
Data Source
AI summary
A wireless base station that performs data communication using a plurality of sub carriers, and repeatedly generates frame patterns comprising one combination or more of at least two types of frames in which the number of common pilots in each is different, and transmits data for mobile terminals having poor receiving quality in a frame having a large number of common pilots, and transmits data for mobile terminals having good receiving quality in a frame having a small number of common pilots.