Inter-cell Interference Coordination via Subframe Segmentation
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Solution Overview
Problem
In heterogeneous wireless communication systems, inter-cell interference occurs due to strong signals from macro base stations affecting micro base stations and vice versa, leading to reduced communication efficiency and accuracy.
Innovation Solution
A method is introduced where channel state information (CSI) measurement resources are determined and allocated by base stations, with specific subframe sets designated for CSI measurement, allowing terminals to perform measurements and report back, while base stations adjust transmission to minimize interference by silencing or reducing power in specific subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If macro base stations and micro base stations operate simultaneously in overlapping coverage areas, then network coverage and capacity are improved, but inter-cell interference increases reducing communication efficiency
Solution Approach 1:
The downlink subframes are segmented into two distinct sets: first downlink subframe sets where the interfering base station transmits, and second downlink subframe sets where the interfering base station is silenced. This temporal segmentation allows the served base station to transmit data in both subframe sets while the interfering base station alternates between transmitting and silencing, thereby reducing inter-cell interference and improving communication efficiency for terminals in overlapping coverage areas.
2Reliability
If base stations transmit continuously to maintain service, then network availability is improved, but inter-cell interference increases reducing measurement accuracy
Solution Approach 1:
The serving base station determines the second downlink subframe set based on the first downlink subframe set information received from the interfering base station before actual transmission. This preliminary determination allows the serving base station to proactively identify subframes where interference will occur and adjust its transmission strategy accordingly, ensuring accurate CSI measurements can be performed in low-interference subframes while maintaining continuous network availability.
3Productivity
If interfering base station transmits in all subframes, then its service capacity is maximized, but interference to served base station increases
Solution Approach 1:
The interfering base station adopts periodic action by alternating between transmitting in first downlink subframe sets and silencing in second downlink subframe sets. This periodic transmission pattern ensures that the interfering base station maintains its service capacity during active subframes while providing relief from interference during silent subframes, allowing the served base station to communicate with terminals in overlapping areas without severe interference.
Data Source
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AI summary
Disclosed herein is a wireless communication system. More particularly, disclosed herein is a method and apparatus for coordinating and reducing inter-cell interference in a wireless communication system. A method of transmitting channel state information (CSI) measurement resource information by a base station includes determining first and second subframe sets, in which CSI measurement will be performed, among a plurality of downlink subframes, transmitting information indicating the first and second subframe sets to a terminal, and receiving the CSI of each of the first and second subframe sets from the terminal. A subframe belonging to the first subframe set and a subframe belonging to the second subframe set do not overlap, and some of the plurality of subframes do not belong to either of the first and second subframe sets.