MIMO-OFDMA Access Node Antenna Selection Subband Handoff
Solution Overview
Problem
Current CDMA-based cellular data networks face inefficiencies in processing increasing data demands, particularly with real-time data like VoIP, and struggle to maximize existing infrastructure while maintaining latency and throughput requirements.
Innovation Solution
The implementation of MIMO-OFDMA technology with antenna selection and subband handoff mechanisms, which includes an access node with encoders, multiplexers, and transmitters to generate and transmit preamble signals and subbands, and access terminals with antennas and multiplex equalization and demodulation elements to optimize data processing and minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CDMA-based cellular data networks are used to process increasing data demands, then data throughput and capacity are improved, but network infrastructure utilization efficiency deteriorates and interference increases
Solution Approach 1:
The patent divides the available bandwidth into multiple subbands (e.g., first subband, second subband, third subband, fourth subband) and assigns different subbands to different access terminals based on channel conditions and data requirements. This segmentation allows efficient utilization of network infrastructure by matching specific frequency resources to specific users, thereby improving overall system throughput while maintaining infrastructure utilization efficiency.
Solution Approach 2:
The patent introduces spatial dimension through MIMO (Multiple-Input Multiple-Output) technology by utilizing multiple antennas at both transmitter and receiver ends. This adds a spatial dimension to the traditional frequency-domain CDMA approach, enabling simultaneous service of multiple users with different quality requirements without proportionally increasing infrastructure complexity, thus improving throughput while maintaining infrastructure utilization.
2Productivity
If MIMO-OFDMA with antenna selection is implemented, then spectral efficiency and network coverage are improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic antenna selection and subband handoff mechanisms where the system can adaptively switch between different antennas and subbands based on real-time channel conditions. This dynamic adaptation allows the system to maintain high spectral efficiency by utilizing the best available resources while managing device complexity through algorithmic optimization rather than hardware complexity.
Solution Approach 2:
The patent utilizes parameter changes in modulation schemes (e.g., changing between first and second modulation schemes based on channel conditions) and adjusts transmission parameters dynamically. This allows the system to optimize spectral efficiency by selecting appropriate parameters for different operating conditions while managing complexity through parameter-based adaptation rather than structural complexity.
3Productivity
If subband handoff mechanisms are used, then data processing optimization is achieved, but latency increases
Solution Approach 1:
The patent performs preliminary actions by pre-configuring multiple subbands and antennas with their respective modulation schemes and channel conditions before actual data transmission begins. This preliminary setup allows for faster switching and handoff during operation, as the system only needs to switch between pre-configured resources rather than configuring everything in real-time, thereby reducing latency while maintaining processing optimization.
Data Source
AI summary
An access node wirelessly coupled to a plurality of access terminals, having a subband scheduler, a plurality of orthogonal frequency division multiplex elements, and a plurality of antennas. The subband scheduler receives precoded data, and schedules transmission of a preamble signal and a plurality of data streams. The plurality of orthogonal frequency division multiplex elements converts the preamble signal and the plurality of data streams into a corresponding preamble tone and a corresponding plurality of data tones. The preamble tone indicates a mapping of the plurality of data tones to one or more of the plurality of access terminals. The plurality of antennas transmits the corresponding preamble tone and the corresponding plurality of data tones in timely fashion for receipt by the plurality of access terminals. The corresponding preamble tone and the corresponding data tones are transmitted over subbands of a code division multiple access (CDMA)-based carrier frequency.