Dynamic Virtual Cell Index Field Length in DCI Signaling
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Solution Overview
Problem
In LTE wireless communication networks, the signaling of virtual cell identity in downlink control information (DCI) leads to high control channel overhead due to the varying size of the DCI based on the number of configured virtual cells, which is inefficient and increases the load on the PDCCH control channel.
Innovation Solution
A method to dynamically set the length of the virtual cell index field in DCI based on the number of configured virtual cell identities, allowing for efficient transmission by setting the field length to zero when no or only one virtual cell is configured, and using log2(N) bits when multiple virtual cells are configured, thereby minimizing the bit field size and reducing signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the virtual cell index field length is increased to support multiple virtual cell configurations, then the adaptability of the system is improved, but the control channel overhead increases
Solution Approach 1:
The patent applies dynamics by making the virtual cell index field length adjustable rather than fixed. The field length is dynamically set based on the number of configured virtual cells: when N>1 virtual cell is configured, the field length is set to log2(N) bits; when N≤1, the field length is set to 0 bits. This dynamic adjustment allows the system to adapt to different configuration scenarios while minimizing control channel overhead in each case.
2Loss of information
If the DCI size is increased to include virtual cell index information, then the information completeness is improved, but the control channel capacity is reduced
Solution Approach 1:
The patent changes the parameter of the virtual cell index field length based on the configuration scenario. When multiple virtual cells are configured (N>1), the field length is set to log2(N) bits to provide complete virtual cell index information. When one or zero virtual cells are configured (N≤1), the field length is set to 0 bits, eliminating redundant signaling. This parameter change ensures information completeness is maintained only when necessary, thereby preserving control channel capacity.
Data Source
AI summary
Methods, network nodes and wireless devices for determining a virtual cell index field length. According to one aspect, a method of determining a length of a virtual cell index field to be transmitted with downlink control information, DCI, is performed where the virtual cell index field length for transmitting a virtual cell index to a wireless device is dynamically settable. The method includes determining a number of configured virtual cell identities, ID. The method includes transmitting the configured virtual cell identities to the wireless device. When a number of configured virtual cell IDs is greater than one, the method includes selecting a virtual cell index corresponding to a particular one of the virtual cell IDs and setting the virtual cell index field length based on the number of virtual cell IDs. The method includes transmitting the selected virtual cell index in the virtual cell index field to the wireless device.