SA Preamble Sub-Block Allocation for Power Balance
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Solution Overview
Problem
In broadband wireless communication systems using OFDM, there is a need for an efficient method to distribute sub-blocks of the Secondary Advanced (SA) preamble across multiple transmit antennas to maximize transmit power utilization and avoid power imbalance, particularly when using irregular channel bandwidths.
Innovation Solution
The method involves determining a sequence for the SA preamble based on the transmit bandwidth, allocating sub-blocks to multiple antennas such that the number of sub-blocks per antenna falls within two consecutive integers, and using the Tone Dropping scheme to maintain subcarrier spacing, as outlined in Equations 1 and 2, ensuring uniform distribution and optimal power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sub-blocks of the SA preamble are distributed to multiple transmit antennas, then the base station identification capability is improved, but the transmit power distribution becomes unbalanced
Solution Approach 1:
The SA preamble sequence is divided into multiple sub-blocks that are distributed across different transmit antennas. This segmentation allows the base station to transmit identification information through multiple antennas simultaneously, improving identification capability while enabling controlled power distribution across the segmented antenna groups
Solution Approach 2:
Different sub-blocks are allocated to different transmit antennas based on local power availability and channel conditions. This local quality approach ensures that each antenna transmits with appropriate power levels, maintaining overall power balance while achieving effective base station identification through the combined signal
2Productivity
If multiple transmit antennas are used to transmit the preamble, then the transmission efficiency is improved, but the complexity of sub-block allocation increases
Solution Approach 1:
The sub-block allocation scheme is predetermined and standardized before transmission. The base station and terminal agree in advance on the mapping relationship between sub-blocks and antennas, eliminating the need for complex real-time allocation decisions and reducing system complexity while maintaining high transmission efficiency
Solution Approach 2:
The patent employs Tone Dropping scheme that adjusts subcarrier spacing parameters based on irregular channel bandwidths. By changing the subcarrier spacing parameter, the system adapts to different bandwidth conditions without requiring complex allocation algorithms, thus improving transmission efficiency while controlling complexity
3Power
If the sub-blocks are uniformly distributed across antennas, then the power utilization is maximized, but the adaptability to irregular channel bandwidths is reduced
Solution Approach 1:
The subcarrier spacing is dynamically adjusted according to the channel bandwidth characteristics. For irregular bandwidths, the Tone Dropping scheme modifies the subcarrier spacing to fit the available spectrum, allowing the system to maintain optimal power utilization across diverse bandwidth scenarios rather than being constrained to fixed uniform distributions
Data Source
AI summary
Preamble transmission in a broadband wireless communication system is provided. A method for transmitting a preamble includes determining a sequence as the preamble according to a transmit bandwidth, allocating sub-blocks of the sequence to a plurality of transmit antennas used to transmit the preamble, the number of the sub-blocks allocated to each antenna falling within two consecutive integers, and transmitting the preamble through the plurality of the transmit antennas according to the allocation result of the sub-blocks.