Narrowband Reference Signal Transmission for Bandwidth Maintenance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication systems face challenges in maintaining minimum bandwidth criteria when one or more downlink carriers are inactive, as they do not meet the required bandwidth threshold, leading to inefficiencies in resource utilization.
Innovation Solution
A base station identifies periods of inactivity on downlink carriers during transmission time intervals and transmits narrowband reference signals (NB-RSs) according to a channel reservation NB-RS pattern, which includes a baseline and supplemental set of time-frequency resources, to ensure continuous signal transmission and meet bandwidth requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If downlink carriers are deactivated to save resources, then resource utilization is improved, but minimum bandwidth criteria cannot be maintained
Solution Approach 1:
The base station transmits NB-RS signals in advance during inactive periods on downlink carriers before actual data transmission is needed. This preliminary action maintains the bandwidth criteria metronomically so that when carriers become active, the minimum bandwidth requirements are already satisfied, avoiding the need to keep carriers continuously active.
Solution Approach 2:
Instead of continuous transmission, the patent implements periodic transmission of NB-RS signals at specific intervals during inactive periods. This periodic action maintains bandwidth criteria only when necessary, allowing carriers to remain inactive most of the time while still meeting minimum bandwidth requirements periodically, thus optimizing resource utilization.
2Reliability
If downlink carriers remain active continuously, then minimum bandwidth criteria are maintained, but resource utilization deteriorates
Solution Approach 1:
The base station performs preliminary bandwidth maintenance by transmitting NB-RS signals during inactive periods before actual communication needs arise. This ensures that when carriers are needed, the bandwidth criteria are already met, allowing carriers to be deactivated most of the time rather than remaining continuously active.
Solution Approach 2:
The system uses the inactive periods themselves to perform the bandwidth maintenance function through NB-RS transmission. Rather than needing separate dedicated resources or continuous activity, the system serves its own bandwidth maintenance needs during otherwise unused inactive periods, eliminating the waste of continuous carrier activation.
3Reliability
If NB-RS transmission is added during inactive periods, then bandwidth criteria are maintained, but system complexity increases
Solution Approach 1:
The NB-RS signals serve multiple functions simultaneously: they maintain bandwidth criteria metronomically, provide reference signals for channel estimation, and utilize inactive periods for transmission. This multi-functionality means that adding NB-RS transmission during inactive periods does not merely add complexity for bandwidth maintenance alone, but provides multiple benefits from a single mechanism.
Solution Approach 2:
The patent changes the transmission parameters of reference signals by transmitting them during inactive periods rather than only during active periods. This parameter change (timing of transmission) allows the system to maintain bandwidth criteria without requiring fundamental changes to the signal structure or additional complex mechanisms, simply by changing when signals are transmitted.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods, systems, and devices for wireless communications are described. A base station may identify a plurality of downlink carriers for a transmission time interval (TTI), e.g., a subframe. The base station may identify a period of inactivity for one or more of the plurality of downlink carriers during the TTI, which may correspond to one or more orthogonal frequency division multiplexing (OFDM) symbols of the subframe. The base station may transmit narrowband reference signals (NB-RSs) over the one or more carriers during the period of inactivity according to a channel reservation narrowband reference signal (NB-RS) pattern. The channel reservation NB-RS pattern may include a first set of time-frequency resources associated with a baseline NB-RS pattern and a second set of supplemental time-frequency resources associated with a period of inactivity.