Scaling Transmission Power Of Uplink Signals Of A Wireless Device

What is this patent about?

’549 is related to the field of wireless communication, specifically addressing power control in scenarios where a wireless device communicates using multiple carrier frequencies. Modern cellular systems, like LTE, often employ carrier aggregation to increase data rates. This involves using multiple frequency bands simultaneously. However, regulatory limits and hardware constraints impose limits on the total transmit power a device can use.

The underlying idea behind ’549 is to enable a wireless device to manage its transmit power effectively when using multiple frequency bands, each potentially having its own power limitations. The device receives information about the maximum allowed transmit power for each frequency band (or group of cells operating on that band). If the device determines that the combined power required for transmission on all bands exceeds the limits, it scales down the power of individual signals to comply with the maximum total transmit power for each band.

The claims of ’549 focus on a wireless device receiving radio resource control (RRC) messages from a base station. These messages contain power parameters that define the maximum total transmit power for different groups of cells operating on different frequency bands. The device then determines if the total power needed for transmission on each group exceeds its limit. If so, it scales down the transmission power of signals within each group to stay within the allowed power budget and transmits the signals.

In practice, the wireless device calculates the required transmit power for each signal based on factors like modulation, coding, and channel conditions. It then sums the power requirements for all signals within each frequency band. If the sum exceeds the maximum allowed power for that band, a scaling factor is applied to reduce the power of one or more signals. The patent suggests prioritizing signals based on factors like the type of data being transmitted (e.g., control data versus user data) or the cell type (licensed vs. unlicensed).

’549 differentiates itself from prior approaches by providing a mechanism for managing transmit power across multiple frequency bands with potentially different power limits. Older systems often treated all carriers as a single entity, potentially leading to inefficient power allocation or violation of regulatory limits. By considering the power constraints of each frequency band separately, the invention allows for more flexible and efficient use of available transmit power, improving overall system performance and compliance.