Pilot Configuration for Distributed MIMO in Heterogeneous Networks
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Solution Overview
Problem
In heterogeneous mobile communications networks, MIMO-capable mobile devices face challenges in achieving optimal performance due to the limitations of existing deployment scenarios, particularly in combined cells where low power nodes do not efficiently utilize spatial multiplexing gains, leading to suboptimal data transmission and increased signaling requirements.
Innovation Solution
The method involves configuring pilot signals adaptively based on the number of MIMO-capable mobile devices in the cell, enabling Distributed MIMO (D-MIMO) mode by determining which devices benefit from spatially separated antennas, and adjusting transmission settings to optimize data transmission between macrocell and low power base stations, allowing for improved spatial reuse and multiplexing gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If pilot signals are transmitted by all base stations in a combined cell, then coverage is improved, but signaling overhead increases and spatial multiplexing gains are not utilized
Solution Approach 1:
The patent applies local quality by differentiating pilot signal transmission based on device location and capability. MIMO-capable devices receive pilot signals from multiple base stations (macrocell and low power node) to enable spatial multiplexing, while non-MIMO devices receive pilot signals from a single base station. This localized differentiation optimizes both coverage and signaling efficiency for different device types in different spatial locations.
Solution Approach 2:
The patent segments the combined cell into multiple coverage areas (macrocell coverage area and low power node coverage area) with distinct pilot signal transmission strategies. By dividing the cell into segments with different transmission characteristics, the system can optimize pilot signal usage for spatial multiplexing in specific segments while reducing overall signaling overhead.
2Productivity
If Distributed MIMO mode is enabled for all devices, then spatial multiplexing gains are achieved, but device compatibility and complexity increase
Solution Approach 1:
The patent implements dynamic configuration of D-MIMO mode based on real-time assessment of device MIMO capability. The network node determines whether each device can benefit from D-MIMO and configures pilot signal transmission accordingly. This dynamic adaptation enables high data transmission rates for capable devices while maintaining simplicity and compatibility for devices that cannot utilize spatial multiplexing.
Solution Approach 2:
The patent changes the pilot signal transmission parameters (number of transmitting base stations, pilot signal configuration) based on device MIMO capability. By adjusting these parameters dynamically, the system achieves high productivity for MIMO-capable devices without imposing unnecessary complexity on non-MIMO devices.
3Productivity
If low power nodes are deployed in combined cells, then network capacity increases, but pilot signal interference and resource allocation complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring pilot signal transmission parameters before data transmission begins. The network node determines device capability and configures the appropriate pilot signal transmission mode in advance, which simplifies subsequent resource allocation and reduces interference management complexity during active data transmission.
Solution Approach 2:
The patent implements feedback mechanisms where devices report their MIMO capability and channel conditions to the network node. This feedback enables the network to optimize pilot signal transmission from low power nodes, managing interference effectively while maximizing network capacity utilization.
Data Source
AI summary
Method and apparatus for pilot configuration in a mobile communications network There is provided a method of operating a central scheduler node in a mobile communications network when one or more mobile devices are located in the coverage area of a first base station and a second base station, the first base station and the second base station having a shared cell identity, the method comprising determining (101) the number of mobile devices that may benefit from a distributed multiple input/multiple output, D-MIMO, mode in which data is transmitted to a mobile device by the first base station and the second base station; and if the number of mobile devices that may benefit from a D-MIMO mode exceeds a threshold, causing (103, 107, 109) said mobile devices, the first base station and the second base station to be configured to operate in the D-MIMO mode.