Codeword-Level Interference Cancellation via Network Signaling
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Solution Overview
Problem
Current LTE systems face challenges in efficiently canceling or suppressing co-channel interference due to the complexity of estimating interference characteristics, particularly in multi-user multiple-input multiple-output (MU-MIMO) transmissions, where intra-cell and inter-cell interference is prevalent, and existing signaling methods are inadequate for providing necessary parameters for interference cancellation.
Innovation Solution
A method is proposed where a receiver derives and receives additional parameters related to interfering signals from the network, including scrambling rules and resource block allocation information, to facilitate Codeword-Level Interference Cancellation (CWIC), reducing the complexity of interference estimation and enhancing cancellation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the receiver blindly detects interference characteristics without network assistance, then the receiver can operate autonomously, but the complexity cost becomes very huge to estimate parameters
Solution Approach 1:
The network acts as an intermediary by providing assistance information about interfering signals (scrambling codes, resource allocation, modulation and coding schemes) to the victim receiver. This mediator approach reduces the receiver's burden of blindly detecting all interference parameters, thereby reducing complexity while maintaining autonomous operation capability
Solution Approach 2:
The network performs preliminary actions by pre-calculating and signaling interference characteristics before the victim receiver needs to process the interfered signal. This advance provision of interference parameters (such as scrambling codes and resource allocation) enables the receiver to perform interference cancellation more efficiently without undertaking the heavy burden of complete parameter detection
2Reliability
If the receiver uses codeword-level interference cancellation (CWIC), then interference cancellation performance is improved, but more information on interference is required such as MCS index and scrambling rules
Solution Approach 1:
The network serves as an intermediary that provides the additional interference information (MCS index, scrambling rules, resource allocation) required for CWIC. Instead of the receiver having to detect all these parameters autonomously, the network mediates by signaling this information, thereby enabling high-performance CWIC without the receiver bearing the full information acquisition burden
Solution Approach 2:
The interference cancellation process is segmented into two parts: (1) the network provides essential interference parameters through signaling, and (2) the receiver uses these parameters to perform CWIC. This segmentation allows the receiver to achieve reliable interference cancellation without needing to independently acquire all interference characteristics
3Device complexity
If the current LTE system provides signaling and reference signals for desired-signal link only, then the system maintains simplicity, but the reliability to estimate interference parameters is insufficient
Solution Approach 1:
The system performs preliminary action by having the network signal interference parameters (such as scrambling codes, resource allocation, MCS) before the victim receiver needs to estimate them. This advance signaling improves measurement precision without requiring complex changes to the overall signaling architecture
Solution Approach 2:
The existing signaling infrastructure is extended to serve multiple functions: it continues to provide desired-signal link information while also providing interference parameter information. This multi-functionality approach improves interference estimation reliability without significantly increasing system complexity
Data Source
AI summary
A method for a receiver to cancel or suppress co-channel interference with network assistance is provided. The method comprises deriving a first set of parameters related to interfering signals in a mobile communication network; receiving a second set of parameters related to the interfering signals from the network; and cancelling the contribution of interfering signals from the received signal based on the combination of the first set and second set of parameters. In one embodiment, scrambling rules and resource block allocation information are signaled to the victim UE to facilitate Codeword-Level Interference Cancellation (CWIC). While the scrambling rule for control channel is based on UE-specific identity, the scrambling rule for data channel is based on cell-specific identity or other network-configurable identity to facilitate CWIC. In addition, RA-allocation information are signaled to the victim UE in an efficient way.