Complementary IQ Sample Exchange for COMP Base Stations
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Solution Overview
Problem
Inter-site cooperation in Coordinated MultiPoint (COMP) operation for cellular communication networks faces challenges due to the need for high-speed interfaces, which are costly to deploy and inefficient in exchanging In-phase and Quadrature-phase (IQ) samples between radio base stations.
Innovation Solution
A method and configuration for radio base stations to extract and transmit complementary IQ samples in a selected subset of the available frequency band and/or antennas, reducing the bit rate required for the interface between cooperating base stations, and using multicasting to efficiently exchange these samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inter-site cooperation is implemented using existing high-speed interfaces, then IQ samples can be exchanged between radio base stations, but the deployment cost becomes very high
Solution Approach 1:
The patent segments the frequency band into multiple sub-bands and selectively exchanges IQ samples only for specific sub-bands between cooperating base stations. This segmentation approach reduces the total volume of data that needs to be transmitted over the interface, thereby reducing the requirements for high-speed interfaces and deployment costs while maintaining COMP operation capability
Solution Approach 2:
The patent extracts and transmits only the necessary complementary IQ samples from specific frequency sub-bands and antenna elements, rather than exchanging all IQ samples. This extraction of essential information reduces the data rate requirement for the interface between base stations, making the system more economically viable
2Loss of information
If all IQ samples are exchanged between cooperating base stations, then complete signal information is available for decoding, but the data rate requirement for the interface becomes very high
Solution Approach 1:
The patent applies local quality by identifying and transmitting only those IQ samples from specific frequency sub-bands and antenna elements that are most beneficial for decoding user data. This selective approach ensures that the most important signal information is exchanged while minimizing the overall data rate requirement
Solution Approach 2:
The patent implements partial action by exchanging IQ samples for only a selected subset of frequency sub-bands and antenna elements rather than all available resources. This partial exchange is sufficient to achieve the decoding goal while significantly reducing the interface data rate requirement
Data Source
AI summary
A supporting radio base station (100) comprises an IQ sample provider (110) for extracting, in a selected subset of the available frequency band (A) and/or from a selected subset of the available antennas (B), so-called complementary IQ samples based on received radio signals including a radio signal originating from an uplink transmission of at least one UE served by a serving radio base station (200). The supporting radio base station (100) comprises an IQ sample transmitter (120) for transmitting the complementary IQ samples to the serving radio base station (200) to enable the serving radio base station to decode user data of the uplink transmission based on the complementary IQ samples together with own IQ samples provided by the serving radio base station (200). This will provide significant savings of bit rate for the exchange of IQ samples between the radio base stations.