Coordinated Downlink MIMO Architecture for Inter-Cell Interference
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Solution Overview
Problem
Conventional MIMO techniques in wireless communication systems fail to address inter-cell interference caused by uplink and downlink transmissions in neighboring cells, limiting spectral efficiency and air-interface performance.
Innovation Solution
Implementing a method for coordinating downlink transmissions from multiple base stations to mobile units using a control plane entity that receives channel state information and determines transmission formats to ensure coherent combining of signals at the mobile unit, thereby suppressing mutual interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional MIMO techniques are used to transmit multiple independent signals from multiple antennas at a base station, then spectral efficiency is increased, but inter-cell interference from neighboring cells is not suppressed
Solution Approach 1:
The patent merges transmission resources across multiple base stations by coordinating downlink transmissions to mobile units. Multiple base stations transmit coherent signals to the same mobile unit using coordinated transmission formats, effectively combining their transmission capabilities while suppressing inter-cell interference through coordinated resource allocation and signal phase alignment.
Solution Approach 2:
The patent introduces a coordination mechanism as an intermediary between base stations. The coordination involves exchanging signaling messages between base stations to align transmission formats, timing, and resource allocation, thereby enabling coherent combining at the mobile unit while suppressing interference from non-coordinated transmissions.
2Reliability
If multiple base stations transmit concurrent signals to mobile units, then signal strength and SINR are improved through coherent combining, but coordination complexity between base stations increases
Solution Approach 1:
The patent employs universal transmission formats that can be applied across multiple base stations. These coordinated transmission formats serve multiple functions: they enable coherent signal combining at the mobile unit, facilitate interference suppression, and provide a standardized framework for inter-base station coordination, thereby reducing overall system complexity.
Solution Approach 2:
The patent changes key transmission parameters including phase, amplitude, and timing offsets of signals from different base stations. By adjusting these parameters through coordinated transmission formats, the system achieves coherent combining at the mobile unit while managing the coordination complexity through parameter optimization rather than complex structural changes.
3Object-affected harmful factors
If base stations exchange signaling messages to coordinate scheduling, then inter-cell interference is reduced, but network overhead and processing delay increase
Solution Approach 1:
The patent implements preliminary coordination between base stations where transmission formats, resource allocations, and timing information are exchanged and agreed upon before actual data transmission. This preliminary action establishes the coordination framework in advance, allowing subsequent transmissions to proceed with reduced signaling overhead and minimal processing delay.
Solution Approach 2:
The patent employs periodic coordination signaling between base stations rather than continuous exchange. Transmission formats and coordination information are updated at periodic intervals, which reduces the frequency of signaling messages while maintaining effective interference suppression. This periodic approach balances coordination overhead with interference management effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances spectral efficiency and air-interface performance by reducing mutual interference between signals from different base stations, improving signal strength and SINR for mobile units.
Implementation Method 1
downlink transmissions from the plurality of base stations combine coherently at said at least one mobile unit when said transmission formats are used
Implementation Method 2
Constructive and/or destructive interference of coherent radiation from the multiple antennas can therefore be used to amplify the signal in selected directions
Data Source
Figure 1
Figure 2~3
AI summary
The present invention provides a method of coordinating the downlink transmissions from a plurality of base stations to at least one mobile unit. The method is implemented in a control plane entity and includes receiving, at the control plane entity and from each of the plurality of base stations, channel state information for a plurality of wireless communication channels between the plurality of base stations and one or more mobile units. The method also includes determining, at the control plane entity and based on the channel state information, transmission formats for downlink transmissions from the plurality of base stations to the mobile unit(s). The method further includes providing the transmission formats to the plurality of base stations.