Hybrid TDD-FDD Duplexing for Wireless Resource Allocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current duplexing techniques, such as TDD and FDD, face inefficiencies in large cell radii environments due to asymmetrical communication challenges and interference, and fail to flexibly manage uplink and downlink resource allocation according to traffic characteristics, limiting their ability to provide high-quality multimedia services.
Innovation Solution
A hybrid duplexing method that dynamically allocates resources by dividing the system frequency band into TDD and FDD intervals, allowing for flexible control of uplink and downlink traffic based on proximity to the access point and cell boundaries, thereby optimizing resource management and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If TDD is used to enable asymmetrical communication, then transmission efficiency is improved, but transmission efficiency decreases when cell radius increases due to RTD
Solution Approach 1:
The system segments the cell into two regions: a first cell region using TDD for asymmetrical communication and a second cell region using FDD for large cell radius communication. This segmentation allows each region to use the most appropriate duplexing technique for its specific requirements.
Solution Approach 2:
The system dynamically determines whether to use TDD or FDD based on the cell radius and communication requirements. The base station can flexibly switch between TDD and FDD modes for different cell regions, making the system adaptable to varying transmission conditions.
2Productivity
If FDD is used to eliminate RTD in large cell radius environments, then transmission efficiency is improved, but asymmetrical transmission becomes difficult
Solution Approach 1:
The system divides the communication system into two parts: FDD for the second cell region (large cell radius) to eliminate RTD, and TDD for the first cell region (small cell radius) to enable asymmetrical transmission. Each part uses the duplexing technique best suited for its requirements.
Solution Approach 2:
Different duplexing techniques are applied to different spatial regions: FDD is applied to the second cell region where large cell radius is the primary concern, while TDD is applied to the first cell region where asymmetrical transmission is the priority. This local optimization resolves the contradiction.
3Adaptability or versatility
If dual-band duplexing is used to support both TDD and FDD, then resource allocation flexibility is improved, but terminal manufacturing cost increases due to multi-mode MODEM requirement
Solution Approach 1:
The base station applies different duplexing modes to different cell regions and user equipment based on their specific requirements. Terminals only need to support the duplexing mode applicable to their region, reducing the need for expensive multi-mode MODEMs while maintaining resource allocation flexibility at the network level.
Solution Approach 2:
The base station acts as an intermediary that manages the duplexing mode selection and resource allocation. It determines whether TDD or FDD should be used for each terminal based on cell radius and traffic conditions, eliminating the need for terminals to have built-in multi-mode capability.
4Adaptability or versatility
If TDD is used in multi-cell environment with different asymmetry rates, then asymmetrical communication is enabled, but serious frequency interference occurs between terminals at cell boundaries
Solution Approach 1:
The system segments the multi-cell environment into different regions with different duplexing modes. Cell boundaries are managed by assigning appropriate duplexing modes (TDD or FDD) based on the specific asymmetry requirements and interference conditions of each cell region, reducing frequency interference at boundaries.
Solution Approach 2:
The system changes the duplexing mode parameter (TDD or FDD) for different cell regions and adjusts asymmetry rates according to local conditions. This parameter adaptation allows asymmetrical communication while minimizing frequency interference between neighboring cells by selecting the appropriate mode for each region.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A resource allocation method in a wireless communication system for providing a communication service in a given system frequency band to access terminals (ATs) within a broad-band service area around an access point (AP) and to ATs within a narrow-band service area having a radius larger than the radius of the broad-band service area. In the resource allocation method, the system frequency band is divided into a Time Division Duplexing (TDD) interval and a Frequency Division Duplexing (FDD) interval in time, and the TDD interval and the FDD interval are defined as TDD resources and FDD resources, respectively. The TDD resources are allocated to an AT within the broad-band service area, and the FDD resources are allocated to an AT within the narrow-band service area.