OFDM Wireless Terminal Dynamic Bandwidth Adaptation
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Solution Overview
Problem
Wireless communications systems face inefficiencies in utilizing available bandwidth, particularly in OFDM systems, where leftover bandwidth is often wasted due to fixed bandwidth allocations, and there is a need for flexible adaptation to changes in available bandwidth to meet user demands and optimize bandwidth usage across different sectors and cells.
Innovation Solution
The method involves dynamically adjusting the number of tones and their spacing in frequency bands, allowing wireless communication devices to operate in different modes by transmitting signals on a first number of tones in a narrower frequency band and a second number of tones in a wider frequency band, while maintaining the same number of tones, to fully utilize available bandwidth and adapt to varying bandwidth conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed size frequency bands are used for bandwidth partitioning, then system reliability and ease of operation are improved, but bandwidth utilization efficiency deteriorates due to leftover unused frequency bandwidth
Solution Approach 1:
The patent implements dynamic bandwidth configuration where the number of tones and their spacing can be adjusted based on available bandwidth. The system transitions from fixed bandwidth partitioning to dynamic adaptation, allowing the OFDM signal to utilize varying amounts of bandwidth (e.g., 1.25 MHz, 1.38 MHz, 1.56 MHz) while maintaining reliable operation through controlled transition mechanisms and synchronization protocols.
Solution Approach 2:
The patent changes key parameters of the OFDM system including the number of tones (e.g., 113, 127, 139 tones) and tone spacing (e.g., 11.25 kHz, 12.25 kHz, 13.25 kHz) to match different bandwidth allocations. These parameter adjustments enable the system to fully utilize available bandwidth while maintaining signal integrity and compatibility across different bandwidth configurations.
2Loss of energy
If the number of tones and their spacing is dynamically adjusted, then bandwidth utilization efficiency is improved, but device complexity increases due to multiple modes of operation
Solution Approach 1:
The patent designs a universal OFDM system that can operate across multiple bandwidth configurations using the same fundamental signal processing architecture. The system maintains multi-functionality by supporting different tone spacings and bandwidth allocations without requiring separate hardware implementations, thereby reducing overall device complexity while improving bandwidth utilization.
Solution Approach 2:
The patent implements dynamic configuration mechanisms that allow the system to adapt to different bandwidth conditions through controlled parameter adjustments. Transition mechanisms and synchronization protocols enable the system to switch between operational modes (different tone spacings and bandwidth allocations) without requiring complete reconfiguration, thereby managing device complexity while maintaining high bandwidth utilization efficiency.
3Adaptability or versatility
If different bandwidth allocations are used in different sectors, then adaptability is improved, but difficulty of detecting and measuring increases due to varying band structures
Solution Approach 1:
The patent implements feedback mechanisms where base stations transmit information about their bandwidth configuration and tone spacing to wireless terminals. This feedback enables terminals to accurately detect and measure the operational parameters of each sector, thereby reducing the difficulty of detecting and measuring different band structures while maintaining high adaptability across sectors with different bandwidth allocations.
Solution Approach 2:
The patent employs preliminary synchronization and configuration transmission where base stations provide advance information about their bandwidth and tone spacing parameters before actual data transmission begins. This preliminary action allows wireless terminals to pre-configure their receivers and accurately detect sector parameters, thereby reducing measurement difficulty while maintaining system adaptability.
Data Source
AI summary
More efficient utilization of available bandwidth is implemented in an OFDM wireless communication system. The partitions of bandwidth may be of different sizes and may be different from the original system design parameters. Basic system structure such as the number of tones used and the number of OFDM symbol times in a slot is maintained throughout the system. Bandwidth is varied by adjusting the inter-tone spacing or bandwidth associated with a single tone. As the inter-tone spacing is increased, the OFDM symbol transmission time is decreased following an inverse proportional relationship. A wireless communications device, during a first period of time transmits signals using a first uplink frequency band of a first number of uniformly distributed tones and during a second period of time transmits signals using a second uplink frequency band of a second number of uniformly distributed tones, the second number being the same as the first number, the second frequency band being wider than the first frequency band.