PDCCH Transmission in DwPTS Using Segmented OFDM Symbols
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Solution Overview
Problem
The conflict between primary synchronization signals and physical downlink control channel (PDCCH) signals in downlink pilot time slots (DwPTS) of LTE systems, particularly for smaller bandwidths, where PDCCH cannot be transmitted on the first OFDM symbol due to primary synchronization signal occupancy.
Innovation Solution
A method where the base station (BS) transmits PDCCH signals on one or more symbols in the DwPTS, using different resources than those for primary synchronization signals, allowing flexible allocation based on the number of symbols available, such as transmitting on the second, third, or additional symbols, and potentially using different subcarriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If primary synchronization signals are transmitted on the first OFDM symbol in the DwPTS, then synchronization function is achieved, but PDCCH cannot be transmitted on the first OFDM symbol due to resource conflict
Solution Approach 1:
The patent segments the DwPTS time resources into different OFDM symbols, assigning the first symbol for primary synchronization signals and subsequent symbols (second, third, or fourth symbols) for PDCCH transmission. This temporal segmentation resolves the resource conflict by dividing the transmission timeline into distinct segments for different signals.
Solution Approach 2:
The patent utilizes frequency domain resources (subcarriers) as an additional dimension for resource allocation. By mapping PDCCH to specific subcarriers in the second, third, or fourth OFDM symbols, the system creates a two-dimensional resource allocation scheme (time and frequency) that resolves the conflict between synchronization signals and control channels.
2Productivity
If PDCCH is transmitted on the first OFDM symbol in the DwPTS, then control channel transmission is optimized, but conflict with primary synchronization signals occurs
Solution Approach 1:
The patent extracts the PDCCH transmission from the first OFDM symbol and relocates it to subsequent symbols (second, third, or fourth symbols). This extraction removes the harmful conflict between PDCCH and primary synchronization signals while maintaining PDCCH transmission functionality in the DwPTS.
Solution Approach 2:
The patent introduces intermediate OFDM symbols (second, third, or fourth symbols) as mediators between the first symbol (occupied by synchronization signals) and the PDCCH transmission. These intermediate symbols serve as temporal buffers that eliminate direct conflict while enabling both signal types to coexist in the DwPTS.
3Adaptability or versatility
If the number of OFDM symbols in DwPTS is increased to accommodate PDCCH, then PDCCH transmission capability is improved, but DwPTS structure complexity increases
Solution Approach 1:
The patent applies partial action by transmitting PDCCH on only the necessary number of additional OFDM symbols (second, third, or fourth symbols) rather than requiring the entire DwPTS to be restructured. This partial extension of PDCCH transmission capability achieves the required functionality with minimal structural change to the DwPTS.
Data Source
AI summary
A method for sending physical downlink control channel (PDCCH) signals in downlink pilot time slots (DwPTS) comprises: a base station (BS) transmits the PDCCH signals on one or more symbols in the DwPTS, and resources used for transmitting the PDCCH signals are different from resources used for transmitting primary synchronization signals of synchronization signals. In the present invention, the method for sending the PDCCH signals can solve the problem of conflict between the PDCCH and the primary synchronization signals in the DwPTS by generating a less delay and less impact on other channels.