RRH Sleep Control via Coverage Area Merging in PON Networks
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Solution Overview
Problem
In wireless base station sleep control using a passive optical subscriber network, existing methods fail to efficiently reduce power consumption as setting RRHs to sleep state disrupts user communication, and maintaining ONUs in sleep state does not significantly lower power consumption due to high power usage by power amplifiers in RRHs.
Innovation Solution
A sleep control method that acquires bandwidth usage and cover area information to identify candidate ONUs and RRHs for sleep state, allowing the RRHs to switch to sleep while maintaining another RRH's active state, thus expanding its cover area to compensate for the sleep state RRHs, optimizing power consumption without reducing overall coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If RRHs are set to sleep state to reduce power consumption, then power consumption is reduced, but user communication is disrupted
Solution Approach 1:
The patent merges the coverage areas of multiple RRHs by having an active RRH assume the coverage of a sleep RRH. When an RRH enters sleep state, its coverage area is merged with that of another active RRH, allowing the system to maintain continuous coverage while reducing power consumption. This is achieved through coordinate management where the active RRH is assigned the combined coverage area including the sleep RRH's former area.
Solution Approach 2:
The patent implements dynamic sleep control where RRHs can transition between active and sleep states based on traffic conditions. The system dynamically adjusts which RRHs remain active and which enter sleep state, optimizing power consumption while maintaining service continuity. This dynamic approach allows flexible adaptation to varying network load conditions.
2Use of energy by stationary object
If ONUs are set to sleep state to reduce power consumption, then power consumption is reduced, but the effect is minimal due to high power usage by power amplifiers in RRHs
Solution Approach 1:
The patent extracts the power consumption issue from the ONU level and focuses it at the RRH level. Since power amplifiers in RRHs consume the majority of power, the system targets RRH sleep control rather than relying on ONU sleep control. This extraction identifies the true power consumption bottleneck and directs control actions to the appropriate level where they will be effective.
3Productivity
If the number of small cells is increased to accommodate mobile traffic, then throughput per unit area is improved, but the cost for maintaining and setting optical fibers increases
Solution Approach 1:
The patent merges multiple RRHs into a coordinated system where multiple RRHs share the same optical fiber connection through the PON. Instead of each RRH requiring a dedicated optical fiber connection, multiple RRHs can be served by a single optical fiber through time-division multiplexing, significantly reducing the number of fibers required while supporting multiple small cells.
Solution Approach 2:
The patent implements a universal optical fiber infrastructure where a single optical fiber serves multiple RRHs through the PON system. This multi-functional use of optical fibers allows the network to support multiple small cells without proportionally increasing fiber infrastructure, reducing both cost and complexity while maintaining the ability to accommodate increased mobile traffic.
Data Source
AI summary
Information about usage bandwidths of the ONUs and information about cover areas of the RRHs are acquired. A maximum cover area of each RRH is set. The remaining RRH included in the currently-set cover areas within the maximum cover area of each RRH is identified. The plurality of ONUs, a total usage bandwidth of which is smaller than or equal to an amount of traffic accommodatable by a single ONU, are identified as a sleep candidate ONU group. The ONU and the RRH to be switched to the sleep state are selected. If the maximum cover area of the RRH connected to one of the ONUs included in the sleep candidate ONU group includes a current cover area of the RRH connected to the remaining ONU, the remaining ONU and the RRH connected to them are selected as the ONU and the RRH to be switched to the sleep state.