Dynamic TDD Downlink Subframe Shortening for Resource Flexibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fixed relation between uplink and downlink subframes in Time-Division Duplex (TDD) systems results in inflexible utilization of radio resources, limiting dynamic adjustment to match varying traffic demands and increasing interference between cells.
Innovation Solution
Dynamic TDD systems shorten downlink subframes by omitting one or more symbols at the end of the transmission interval, with signaling in grant messages indicating the shortened subframe duration to both transmitting and receiving nodes, allowing flexible resource allocation and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed relation between uplink and downlink subframes is used in TDD systems, then system simplicity is maintained, but radio resource utilization flexibility deteriorates
Solution Approach 1:
The patent implements dynamic TDD by allowing the downlink subframe length to be variable rather than fixed. The base station can shorten downlink subframes by omitting one or more OFDM symbols at the end, and this dynamic adjustment is signaled to user equipment through grant messages. This enables the system to adapt radio resource allocation to varying traffic demands while maintaining manageable complexity through standardized signaling mechanisms.
2Adaptability or versatility
If downlink subframes are shortened dynamically, then radio resource flexibility is improved, but signaling overhead increases
Solution Approach 1:
The patent changes the parameter of downlink subframe length dynamically by varying the number of OFDM symbols transmitted. Instead of using extensive signaling to describe entire subframe configurations, the system efficiently signals only the deviation from the normal subframe length (i.e., how many symbols are omitted). This parameter-based approach reduces signaling overhead while maintaining the ability to flexibly adjust radio resources according to traffic conditions.
3Device complexity
If fixed subframe structure is used, then processing simplicity is maintained, but user data delay increases
Solution Approach 1:
The patent enables dynamic adjustment of downlink subframe lengths to reduce user data delay. When traffic conditions require faster data delivery, the system can shorten downlink subframes, allowing user data to be transmitted and acknowledged more quickly. This dynamic approach balances processing simplicity with reduced latency by maintaining standard processing procedures while allowing flexible subframe length adaptation.
Data Source
AI summary
A guard period for switching between uplink and downlink subframes is created by shortening a downlink subframe, i.e., by not transmitting during one or more symbol intervals at the end of the subframe. A grant message includes signaling indicating when a shortened subframe is being transmitted. An example method is implemented in a receiving node configured to receive data from a transmitting node in subframes having a predetermined number of symbol intervals. In an LTE system, this receiving node may be a UE, and the subframes are downlink subframes. This example method includes determining that a received subframe is to be shortened, relative to the predetermined number of symbol intervals and, in response to this determination, disregarding a last part of the received subframe by disregarding one or more symbols at the end of the received subframe when processing the received subframe.