Superposition Coding for Wireless Throughput and Fairness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wireless communication systems, such as those using the cdma2000 1xEV-DO standard, face limitations in forward link data throughput performance due to disparities in Signal-to-Interference-and-Noise Ratio (SINR) among users, leading to penalized throughput and increased delays for users with lower SINR, while struggling to provide fair service to all users.
Innovation Solution
The implementation of superposition coding, which selects a combination of users to maximize forward link data throughput by dynamically reallocating power transmission and using different modulation techniques and packet formats, such as OFDM and OFDMA, to create a superposition coded packet that can be transmitted to multiple users, thereby improving spectral efficiency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional intrinsic resource assignment methods are used to provide fair service to all cell phones, then service fairness is improved, but overall system data throughput performance deteriorates
Solution Approach 1:
The patent segments users into different groups based on their SINR levels and service requirements. By dividing the user population into segments (e.g., users needing fair service vs. users capable of higher throughput), the system can apply different resource assignment strategies to each segment, thereby maintaining overall fairness while improving total throughput.
Solution Approach 2:
The patent implements dynamic resource assignment where the base station can adaptively adjust which users receive service and at what rates based on current channel conditions, SINR levels, and system state. This dynamic approach allows the system to optimize throughput in real-time while maintaining fairness constraints, rather than using static intrinsic resource assignment.
2Productivity
If conventional scheduling methods rank cell phones by pilot signal intensity to determine data packet reception, then service to the most deserving user is improved, but delays for remaining users increase
Solution Approach 1:
The patent merges multiple users' data packets into superposition coded packets that can be transmitted simultaneously. By combining packets for multiple users (including both the most deserving user and other users) into a single transmission, the system improves throughput for high-SINR users while reducing waiting delays for other users, as they receive service in the same time slot rather than having to wait for subsequent slots.
Solution Approach 2:
The patent enables continuous service to multiple users by transmitting superposition coded packets that serve multiple users simultaneously. This eliminates idle time slots where only one user is served while others wait, thereby maintaining continuous useful action and reducing overall system latency while preserving high throughput for the most deserving users.
3Productivity
If superposition coding is used to maximize forward link data throughput, then system throughput performance is improved, but system complexity increases
Solution Approach 1:
The patent applies partial superposition coding by limiting the number of users combined in each superposition coded packet (e.g., combining only 2-4 users at a time rather than all users). This partial application reduces the computational complexity of encoding and decoding operations while still achieving significant throughput improvements, avoiding the excessive complexity that would result from combining all users simultaneously.
4Productivity
If power transmission is dynamically reallocated to improve throughput, then data throughput performance is improved, but power management complexity increases
Solution Approach 1:
The patent implements feedback-based power allocation where the base station monitors user SINR levels, channel conditions, and throughput performance, then uses this feedback to dynamically adjust power allocation for superposition coded packets. This feedback mechanism enables automated optimization of power distribution to maximize throughput while managing complexity through rule-based or algorithmic decision-making rather than manual configuration.
Data Source
AI summary
The present patent application comprises a method and apparatus to compile a superposition coded packet by compiling user candidates for superposition coding, ranking the user candidates based on a result of an evaluation function, selecting a deserving user candidate from among the user candidates, and compiling a superposition coded packet by adding other user data packets to a packet of the deserving user data packet, wherein the data packets for the user candidates may conform to a plurality of different formats and wireless communication standards.