Wireless Base Station Bandwidth Segmentation for MTC Coverage
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Solution Overview
Problem
The adoption of a single receive RF chain in wireless communication systems for Machine-Type Communications (MTC) devices leads to a significant cost reduction but results in a 4 dB degradation of cell coverage, necessitating a method to achieve configurable reduced downlink bandwidths and compensate for coverage loss.
Innovation Solution
The method involves transmitting control and data signalling within specific bandwidth regions, using enhanced physical downlink control channels (ePDCCHs) for blind detection, and introducing a System Information Block (SIB) type associated with MTC devices to provide information on downlink reduced bandwidth, uplink carrier frequency, and random access parameters, enabling dynamic resource allocation and coverage compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single receive RF chain is adopted for MTC devices, then device cost is significantly reduced, but cell coverage degrades by 4 dB
Solution Approach 1:
The patent segments the downlink bandwidth into a common control region and a data region, allowing different bandwidth configurations for different signal types. The control region uses full bandwidth for robust control signaling, while the data region can be reduced for cost-effective MTC devices, resolving the contradiction between cost reduction and coverage maintenance.
Solution Approach 2:
The patent applies different bandwidth characteristics to different parts of the spectrum. The control region maintains full bandwidth coverage for reliable control signaling, while the data region can be narrowed down to 1.4 MHz for MTC devices, allowing local optimization that maintains overall system reliability while reducing device cost.
2Device complexity
If downlink bandwidth is reduced to 1.4 MHz for MTC devices, then device cost and complexity are reduced, but spectrum efficiency deteriorates
Solution Approach 1:
The patent segments the bandwidth allocation so that control signaling uses full bandwidth while data transmission uses reduced bandwidth. This segmentation allows the system to maintain spectrum efficiency for control signals while providing cost-effective reduced bandwidth for MTC data traffic.
Solution Approach 2:
The patent introduces dynamic bandwidth configuration where the network can adaptively allocate bandwidth resources based on device type and traffic requirements. MTC devices can be dynamically configured with reduced bandwidth for cost efficiency, while other devices maintain full bandwidth for optimal spectrum utilization.
3Ease of manufacture
If legacy GSM/GPRS networks are used for MTC devices, then device cost is reduced, but network maintenance cost increases due to supporting multiple RATs
Solution Approach 1:
The patent creates a universal LTE-based solution that can serve both MTC devices and traditional LTE devices through a single network infrastructure. By introducing MTC-specific bandwidth configurations within the existing LTE framework, the network can universally support multiple device types without requiring separate GSM/GPRS infrastructure, thereby reducing network complexity while maintaining device cost effectiveness.
Data Source
AI summary
There is provided a method in a wireless base station (300), the method comprise transmitting, to a wireless device (100) having a reduced data bandwidth or a reduced control and data bandwidth, control and data signalling within a first bandwidth, in respective control and data regions, wherein signalling within the data region intended for the wireless device (100) is constrained within a second bandwidth which is narrower than the first bandwidth.