TDD Frame Structure with Flexible Guard Period for Interference Control
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Solution Overview
Problem
The TDD system faces inflexibility in setting the guard period (GP) length, low utilization efficiency of DwPTS, and interference with uplink reception due to high power P/S-SCH signals, especially when coexisting with TD-SCDMA systems at adjacent frequencies.
Innovation Solution
A signal transmission method where a base station transmits in a downlink special time slot, then receives in an uplink special time slot, with the total time length of downlink, guard period, and uplink special time slots being integer multiples of normal time slots, allowing flexible GP setting and improved resource utilization by adjusting the timing of synchronization signals and random access signals within these slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the GP time slot length is extended to support wider coverage, then the coverage is improved, but the flexibility in setting GP is reduced and system resources are wasted
Solution Approach 1:
The patent makes the GP time slot length adjustable and flexible rather than fixed. The base station can dynamically configure the GP length based on actual coverage requirements, allowing the system to adapt between different coverage scenarios (wide coverage vs. normal coverage) while maintaining optimization of system resources.
2Reliability
If the P/S-SCH signals are transmitted with high power for reliable synchronization, then the synchronization reliability is improved, but the uplink reception interference is increased
Solution Approach 1:
The patent segments the time slots into different types (downlink special time slot, guard period, uplink special time slot) and assigns different functions to each. By separating the high-power synchronization signal transmission (in downlink special time slot) from the uplink reception period (uplink special time slot), the system achieves both reliable synchronization and reduced uplink interference.
Solution Approach 2:
The guard period acts as an intermediary buffer between the downlink special time slot (where high-power P/S-SCH signals are transmitted) and the uplink special time slot (where uplink signals are received). This intermediary structure allows the high-power synchronization signals to be transmitted without directly interfering with uplink reception, as the GP provides a protected transition period.
3Reliability
If the DwPTS time slot is used only for P-SCH signal transmission, then the synchronization function is improved, but the resource utilization efficiency is reduced
Solution Approach 1:
The patent makes the downlink special time slot multi-functional by allowing it to carry both the P-SCH synchronization signal and downlink data channels. This universal usage of the DwPTS slot eliminates the previous limitation where only synchronization signals could be transmitted, thereby significantly improving resource utilization efficiency while maintaining the synchronization function.
4Ease of operation
If the UpPTS time slot is used for random access signal transmission, then the uplink access function is improved, but the interference to other base stations is increased
Solution Approach 1:
The patent enables dynamic configuration of the uplink special time slot, allowing the base station to flexibly adjust the timing and duration of uplink signal transmission. This dynamic capability allows optimization of the uplink access function while controlling interference to neighboring base stations through adaptive time slot management.
Data Source
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AI summary
A signal transmission method in a Time Division Duplex (TDD) system is disclosed. The method comprises following steps: within a time length of a half-frame of a radio frame, base station transmits signal on a downlink special time slot, thereafter does not transmit signal on a Guard Period (GP), and then receives signal on an uplink special time slot; all time lengths of other uplink or downlink normal time slots for transmitting signal are equal; the total time length of the downlink special time slot, the guard period and the uplink special time slot is integer times of the time length of an uplink or downlink normal time slot. In addition, a frame structure adopted in the TDD system which corresponds to the method is disclosed. The present invention makes it flexible to set the duration of the GP and it is guaranteed that, even if a synchronization signal adopts power promotion, it will not bring great interference to uplink reception of other base stations; in addition, the utilization efficiency of the system is improved.