Pico-node Synchronization in Heterogeneous Cellular Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In heterogeneous cellular networks, transmissions from macro-nodes and pico-nodes are often unsynchronized, leading to timing and frequency mismatches that complicate signal reception for mobile terminals, especially when pico-nodes do not create distinct cells, causing interference and requiring new UE functionality for alignment.
Innovation Solution
The synchronization of timing and frequency of pico-node transmissions with those from macro-nodes by measuring synchronization signals and cell-specific reference signals, allowing pico-nodes to adjust their transmissions to align with macro-node signals, ensuring time- and frequency-alignment at mobile terminals without requiring changes to existing UE technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pico-nodes transmit independently without synchronization with macro-nodes, then device complexity is reduced and deployment is simpler, but timing and frequency mismatches occur causing interference and requiring new UE functionality
Solution Approach 1:
The patent implements a feedback mechanism where the macro-node measures the timing and frequency of signals received from pico-nodes, calculates offsets, and provides feedback to the pico-nodes. This closed-loop feedback system enables automatic synchronization adjustment without requiring complex UE functionality, resolving the contradiction by maintaining simple UEs while eliminating interference through network-side coordination.
Solution Approach 2:
The macro-node acts as an intermediary that mediates between pico-nodes and UEs. It receives measurements from pico-nodes, calculates timing and frequency offsets, and coordinates transmissions to ensure alignment at the UE. This intermediary approach allows independent pico-node deployment without requiring UEs to handle synchronization complexity, thus reducing device complexity while preventing interference.
2Productivity
If pico-nodes are deployed to improve system capacity and coverage, then network performance is improved, but timing and frequency alignment becomes more difficult without synchronization mechanisms
Solution Approach 1:
The patent implements preliminary synchronization actions where pico-nodes first measure macro-node synchronization signals and cell-specific reference signals to establish initial timing and frequency alignment before data transmissions. This preliminary alignment ensures that subsequent pico-node transmissions are pre-synchronized with macro-nodes, maintaining measurement precision while enabling capacity improvement through heterogeneous deployment.
Solution Approach 2:
The macro-node measures received signal timing and frequency from pico-nodes, calculates offsets, and provides feedback for adjustment. This continuous feedback mechanism maintains high timing and frequency alignment precision as pico-nodes are deployed to improve system capacity, resolving the contradiction by enabling scalable deployment without sacrificing synchronization accuracy.
3Use of energy by moving object
If pico-nodes operate on the same carrier frequencies as macro-nodes to share radio resources, then spectrum efficiency is improved, but interference between layers increases without coordination
Solution Approach 1:
The macro-node serves as an intermediary that coordinates transmissions between macro-nodes and pico-nodes operating on the same carrier frequencies. It measures timing and frequency of pico-node signals, calculates offsets, and provides feedback to ensure aligned transmissions. This coordination enables spectrum efficiency through resource sharing while preventing inter-layer interference through network-side synchronization management.
Data Source
AI summary
A high-power point (110) and one or more low-power points (120) transmit signals associated with the same cell-identifier in a heterogeneous cell deployment. Coverage areas corresponding to the low-power points (120) fall at least partly within the coverage area for the high-power point, so that mobile stations (130) within range of a low-power point are also within range of the high-power point (110). A low-power point (120) measures timing or frequency, or both, of one or more signals received at the low-power point (120) from the high-power point (110), and adjusts the timing or frequency, or both, of a transmission from the low-power point (120) to a mobile station (130), to align the transmission with signals received by the mobile station (130) from the high-power point (110).