Massive MIMO Random Access Beamforming in Millimeter-Wave Networks
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Solution Overview
Problem
Next-generation mobile broadband systems face challenges in achieving 1000 times the capacity of current systems without incurring excessive costs and network overhead, particularly due to the need for frequent handovers and inefficient random access procedures in millimeter-wave environments with multiple antennas.
Innovation Solution
Implementing a method for adaptive random access using multiple antennas at both base stations and user equipment, employing beamforming techniques to optimize beamwidth selection and power ramping for efficient uplink and downlink transmissions, reducing latency and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of cells is increased to achieve 1000 fold capacity increase, then system capacity is improved, but capital and operating costs increase significantly
Solution Approach 1:
The patent combines multiple cell functions into a single base station by implementing massive MIMO with a large number of antennas (e.g., 64 or 128 antennas). This allows one base station to serve multiple spatial directions and multiple users simultaneously, replacing the need for numerous separate small cells while achieving the same capacity increase.
Solution Approach 2:
The patent transitions from horizontal cell division to vertical spatial multiplexing by utilizing the antenna dimension. Through beamforming and spatial division multiple access (SDMA), the system creates multiple virtual channels in the spatial domain, allowing simultaneous service to multiple users without adding physical cells.
2Productivity
If cell size is reduced to increase capacity, then system capacity is improved, but handover frequency increases causing network signaling overhead and latency
Solution Approach 1:
The patent segments the spatial coverage area into multiple directional beams using beamforming technology. Each beam serves a specific spatial sector, allowing the system to maintain larger physical cell sizes while providing targeted service to different spatial regions, thereby reducing handovers as users move within the same cell.
Solution Approach 2:
The patent implements dynamic beamforming that adapts beam directions and widths based on user positions and movements. This dynamic adjustment allows the system to track users within the cell, maintaining optimal connectivity without requiring frequent handovers to adjacent cells.
3Loss of time
If beamforming is used to improve random access efficiency, then access latency is reduced, but device complexity increases due to multiple antennas
Solution Approach 1:
The patent implements periodic beam sweeping where the base station systematically transmits reference signals through different beams in a predetermined sequence. User equipment measures these periodic signals to identify the best beam, converting the complex beam selection problem into a simple periodic measurement and selection process.
Solution Approach 2:
The patent performs preliminary beam training during the random access procedure by transmitting beam-specific reference signals before actual data transmission. This preliminary beam establishment simplifies subsequent communication by pre-configuring the optimal beam paths, reducing the complexity of real-time beam management.
Data Source
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AI summary
A method for performing random access by a User Equipment (UE) in a wireless network, comprises configuring at least one UE transmit beam for a transmission of a random access signal, generating the at least one UE transmit beam using an antenna array according to the configuration, and transmitting the random access signal to a base station (BS) on the at least one UE transmit beam. An user equipment for performing random access in a wireless network, the User Equipment comprises a processing circuit configured to configure at least one UE transmit beam for a transmission of a random access signal, and generate the at least one UE transmit beam using an antenna array according to the configuration, and transmit the random access signal to the Base Station (BS) on the at least one UE transmit beam.