Narrowband Control Channel Resource Allocation for IoT
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Solution Overview
Problem
The increasing number of user equipment (UEs) and the corresponding data and control information that base stations (BS) need to transmit, combined with limited radio resources, necessitate an efficient method for transmitting and receiving uplink/downlink data and control information in wireless communication systems.
Innovation Solution
A method for transmitting and receiving downlink control information (DCI) using a narrowband physical downlink control channel (N-PDCCH) with specific control channel element (CCE) configurations within a limited resource block (RB), allowing efficient use of radio resources, particularly in narrowband Internet of Things (NB-IoT) environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation technology and MIMO technology are used to increase data throughput, then data transmission capacity is improved, but device complexity and resource requirements increase
Solution Approach 1:
The patent segments the control channel resources into narrowband units (1.4 MHz) rather than using wideband resources. By dividing the control channel into smaller, manageable narrowband segments, the system can support multiple UEs with different bandwidth capabilities, including low-complexity devices that only need to process narrowband control information, thereby reducing device complexity while maintaining high overall system throughput through parallel narrowband operations
Solution Approach 2:
The patent applies local quality by providing different control channel configurations for different UE types. Specifically, it introduces narrowband PDCCH (NPDCCH) for low-complexity UEs that operate in 1.4 MHz bandwidth, while wideband UEs can utilize broader bandwidth resources. This localized adaptation allows each UE to operate at its appropriate complexity level without requiring all devices to support full MIMO and carrier aggregation capabilities
2Adaptability or versatility
If the number of user equipment and control information increases, then service coverage is improved, but radio resource availability decreases
Solution Approach 1:
The patent introduces a new dimension for control channel resource allocation by creating separate narrowband control channel resources (NPDCCH) in addition to traditional wideband PDCCH resources. This dimensional separation allows the system to serve both wideband and narrowband UEs simultaneously without one group consuming resources needed by the other, effectively increasing overall service coverage while preserving radio resource availability for different UE categories
Solution Approach 2:
The narrowband control channel design provides universal functionality by being applicable to all UE types. Low-complexity UEs can receive control information in narrowband format, while wideband UEs can also utilize narrowband control channels when needed. This multi-functional control channel approach allows the system to accommodate increasing numbers of diverse UEs without proportionally increasing total control resource consumption
3Ease of manufacture
If narrowband control channel is used for low complexity UE, then device cost is reduced, but control information transmission efficiency may be compromised
Solution Approach 1:
The patent changes key parameters of the control channel to match narrowband UE capabilities. Specifically, it reduces the control channel bandwidth from wideband to narrowband (1.4 MHz), adjusts the resource block allocation accordingly, and modifies the control information structure to fit narrowband constraints. These parameter changes enable low-cost device implementation while maintaining adequate control information transmission efficiency through optimized narrowband resource utilization and appropriate aggregation levels
Data Source
Figure 1(a)~1(b)
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AI summary
A method for downlink control information (DCI) transmission/reception is provided. The method for DCI transmission comprises: receiving, by a user equipment, a narrowband physical downlink control channel (N-PDCCH) carrying the DCI. The N-PDCCH is received using at least one of two control channel element (CCEs) on the 1 resource block (RB) only. A first CCE of the two CCEs occupies 6 subcarriers of the lowest indices among the 12 subcarriers and a second CCE of the two CCEs occupies 6 subcarriers of the highest indices among the 12 subcarriers.