Uplink Beam Selection for Millimeter Wave Path Loss
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Solution Overview
Problem
In millimeter wave wireless communication systems, the existing beamforming techniques are inefficient in terms of energy and inter-MS interference due to the need for beam sweeping across all possible transmission/reception directions, and they struggle to accurately set power for random access signals, especially in systems using omni antennas where path loss varies by beam direction.
Innovation Solution
A method and apparatus for a Mobile Station (MS) to select an optimal UpLink (UL) transmission beam and determine transmission power based on DownLink (DL) path loss measurements, using a beamformer and controller to receive DL reference signals, measure path loss, and select the best transmission beam for UL signal transmission, thereby improving energy efficiency and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam sweeping is performed across all possible transmission/reception directions to establish communication channel, then communication reliability is improved, but energy consumption increases and inter-MS interference worsens
Solution Approach 1:
The patent applies partial action by having the MS transmit random access signal only in the uplink beam direction that was selected during downlink beam training, rather than transmitting in all possible beam directions. This reduces energy consumption and inter-MS interference while maintaining communication reliability through the beam selection process.
2Reliability
If beam sweeping is performed across all possible transmission/reception directions to establish communication channel, then communication reliability is improved, but inter-MS interference increases
Solution Approach 1:
The patent reduces inter-MS interference by limiting the random access signal transmission to only the selected uplink beam direction rather than all possible directions. The beam selection process ensures that only necessary beams are activated, reducing harmful interference to other MS while maintaining communication reliability.
3Device complexity
If random access signal power is set without considering beam direction path loss, then power control simplicity is improved, but transmission success probability deteriorates
Solution Approach 1:
The patent applies preliminary action by performing downlink beam training and path loss measurement before the random access process. The MS measures path loss for different downlink beam directions and selects the optimal uplink beam accordingly. This preliminary beam selection and path loss estimation enables accurate power control for the random access signal, improving transmission success probability without significantly increasing overall system complexity.
Data Source
AI summary
An UpLink (UL) control method and apparatus for in a wireless communication system supporting beamforming are provided. A method of a Mobile Station (MS) for UL control in the wireless communication system supporting the beamforming includes receiving a plurality of DownLink (DL) reference signals from a plurality of Base Station (BS) transmission beams using a plurality of MS reception beams having different directivity, measuring a path loss based on a reception signal strength of each of the plurality of DL reference signals received through different transmission/reception beams, selecting an MS transmission beam for uplink based on the path loss value measured for each of the plurality of DL reference signals, and transmitting a UL signal to a BS using the selected MS transmission beam.