Pilot Boosting and Traffic-to-Pilot Ratio Estimation
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Solution Overview
Problem
In wireless communication systems, the use of multiple antennas for transmit diversity results in inefficient power utilization due to varying power levels across antennas and OFDM symbols, leading to subcarrier resource wastage and degraded system performance.
Innovation Solution
A method where data modulation symbols and reference signal symbols are mapped into transmission resources across multiple antennas, with power scaling factors assigned based on reference signal power levels to maintain a fixed power level across antennas and time units, and channel gains are calculated to optimize power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power levels are kept the same across multiple antennas and OFDM symbols, then system complexity is reduced and ease of operation is improved, but power utilization efficiency deteriorates and subcarrier resources are wasted
Solution Approach 1:
The patent implements dynamic power scaling where the power level for data subcarriers is adjusted based on the presence or absence of pilot subcarriers in each OFDM symbol. The power scaling factor changes dynamically across different OFDM symbols and antennas, allowing the system to adapt power distribution to actual transmission needs rather than maintaining a static uniform power level.
Solution Approach 2:
The patent applies different power scaling factors to different local regions of the transmission resource grid - specifically different OFDM symbols and different antenna ports. Each antenna and each OFDM symbol can have its own power scaling factor, allowing localized optimization of power utilization based on whether pilot symbols are present in that specific time-frequency location.
2Loss of energy
If power levels are varied across antennas and OFDM symbols to optimize power utilization, then power efficiency is improved, but system complexity increases due to the need for power scaling calculations
Solution Approach 1:
The patent introduces power scaling factors as adjustable parameters that modify the power levels of data subcarriers based on pilot subcarrier presence. These parameters (power scaling factors) are calculated using simple ratios involving total transmit power, number of antennas, and pilot configuration, making the complexity manageable while achieving significant power optimization.
Solution Approach 2:
The system uses feedback from the pilot subcarrier configuration to automatically adjust power scaling factors. The presence or absence of pilots in each OFDM symbol provides feedback information that directly determines the power scaling factor to be applied, creating a self-regulating mechanism that optimizes power without requiring complex external control.
3Stability of the object's composition
If subcarrier resources are punctured in OFDM symbols containing pilots to maintain fixed power levels, then power consistency across symbols is improved, but system performance deteriorates due to resource wastage
Solution Approach 1:
Instead of puncturing subcarriers to maintain power consistency, the patent changes the power parameter itself by applying power scaling factors. This allows all subcarriers (including both pilot and data subcarriers) to be utilized while maintaining acceptable power consistency through controlled scaling rather than through resource deletion.
4Ease of manufacture
If uniform power levels are maintained across all antennas, then implementation simplicity is improved, but power utilization efficiency deteriorates when some antennas have extra power available
Solution Approach 1:
The patent implements dynamic power allocation where each antenna can have its own power scaling factor that adjusts based on its specific pilot configuration and available power. This dynamic approach allows the system to exploit available power differences across antennas while maintaining a relatively simple implementation through standardized scaling calculations.
Data Source
AI summary
Methods and circuits for assigning pilot boosting factors and calculating traffic to pilot ratios in a wireless communication system. The data to be transmitted is first modulated to generate a plurality of data modulation symbols. The plurality of data modulation symbols and a plurality of reference signal symbols are mapped into transmission resources of each of a plurality of antennas in accordance with a transmit diversity scheme. The transmission resources of each of the antennas are divided into a plurality of subcarriers in a frequency domain and a plurality of time units in a time domain. Then, a power scaling factor are assigned for data modulation symbols on each of the antennas in dependence upon power levels of the reference signal symbols to maintain a fixed power level across the plurality of antennas in each time unit. Finally, the data modulation symbols and the reference signal symbols are transmitted via the plurality of antennas in accordance with the mapping scheme and the assigned scaling factors.