Distance-Based Downlink Symbol Allocation in TDD Networks
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Solution Overview
Problem
Existing Time Division Duplex (TDD) wireless communication networks face challenges in efficiently allocating system resources for downlink and uplink transmissions due to increased round trip delay and interference as remote devices become more distant from network nodes, limiting the maximum distance between transmission points and consuming more bandwidth.
Innovation Solution
A method where network nodes determine the distance of each remote device and allocate downlink symbols in a frame based on distance, assigning earlier symbols to more distant devices to reduce round-trip delay and interference, thereby optimizing downlink transmission and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed time interval is specified between downlink frame end and uplink frame beginning to allow remote devices to decode and prepare, then remote devices have sufficient time to process downlink data, but the maximum distance between transmitter and remote device is limited and bandwidth consumption increases
Solution Approach 1:
The patent applies dynamics by making the downlink symbol allocation dynamic based on remote device distance. Instead of a fixed time interval for all devices, the system dynamically determines distance (via timing advance values or location information) and allocates downlink symbols accordingly, allowing the frame structure to adapt to varying propagation delays and optimize bandwidth usage.
Solution Approach 2:
The patent changes the parameter of downlink symbol allocation based on remote device distance. By adjusting the number and position of downlink symbols in the frame according to the calculated distance of each remote device, the system optimizes the balance between decoding time and bandwidth efficiency for different propagation conditions.
2Length of stationary object
If the time interval between downlink frame end and uplink frame beginning is increased to accommodate distant devices, then more distant communication is enabled, but round trip delay increases and interference increases
Solution Approach 1:
The patent applies local quality by allocating different downlink symbol positions and durations to remote devices based on their specific distance from the network node. Distant devices receive earlier downlink symbols with sufficient processing time, while closer devices receive later symbols, allowing each device to operate optimally for its specific propagation delay without increasing overall cell radius limitations.
3Device complexity
If downlink symbols are allocated uniformly to all remote devices regardless of distance, then resource allocation is simple, but distant devices experience excessive delay and closer devices waste bandwidth
Solution Approach 1:
The patent changes the resource allocation parameters (downlink symbol positions and durations) based on the distance parameter of each remote device. The network node calculates distance using timing advance values or location information, then adjusts downlink symbol allocation accordingly, optimizing transmission efficiency for each device's specific propagation conditions.
4Loss of time
If the number of cell sites is increased to reduce round trip delay for distant devices, then coverage and responsiveness improve, but network infrastructure cost increases
Solution Approach 1:
The patent applies dynamics by implementing dynamic downlink symbol allocation within existing cell sites. Instead of statically increasing the number of cell sites, the system dynamically adjusts frame structures to accommodate distant devices, reducing round trip delay through optimized symbol timing while maintaining the same network infrastructure.
Data Source
AI summary
A method and apparatus for optimizing downlink transmission in a wireless communication network (100) includes determining (502) a distance of each of a plurality of remote devices (102-114) from a network node (120) and allocating (506) downlink symbols of a frame (300) for the downlink transmission based on the determined distance of each of the plurality of remote devices. Earlier downlink symbols of the frame are allocated to at least one remote device of the plurality of remote devices positioned more distant from the network node in comparison to at least other remote device positioned less distant from the network node.