Off-Center Subchannel Allocation for MTC Coexistence
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Solution Overview
Problem
Current LTE systems do not allow a UE to transmit and receive with a reduced RF bandwidth, limiting the cost reduction and coverage enhancement for Machine-Type Communication (MTC) devices, which are essential for efficient operation and coexistence with traditional UEs in wireless networks.
Innovation Solution
The method involves determining an off-center subchannel within the system bandwidth, mapping its center frequency to a DC subcarrier, and allocating this subchannel to the UE, allowing for reduced RF bandwidth operation while avoiding conflicts with existing resources and ensuring coexistence with non-MTC UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If MTC devices use reduced RF bandwidth (1.4 MHz), then device cost and power consumption are reduced, but the ability to coexist with traditional UEs in existing LTE networks is compromised
Solution Approach 1:
The patent segments the system bandwidth into multiple subchannels, allowing MTC devices to operate on a reduced 1.4 MHz bandwidth portion while traditional UEs continue to use the full bandwidth. This segmentation enables cost reduction for MTC devices while maintaining network compatibility through the subchannel allocation mechanism.
Solution Approach 2:
The patent introduces an intermediary mechanism (subchannel allocation and mapping) that mediates between the reduced bandwidth requirements of MTC devices and the full bandwidth operation of traditional UEs. The network node allocates specific subchannels to MTC devices, enabling coexistence without requiring MTC devices to support full bandwidth.
2Use of energy by moving object
If MTC devices operate with reduced RF bandwidth, then power consumption is reduced, but coverage enhancement capability is limited
Solution Approach 1:
By segmenting the available bandwidth into subchannels, the patent allows MTC devices to operate with reduced RF bandwidth (1.4 MHz) which lowers power consumption, while the network can allocate specific subchannels to provide coverage enhancement in areas with poor signal strength.
Solution Approach 2:
The patent applies local quality by allowing different parts of the network to have different bandwidth allocations. MTC devices can be allocated specific subchannels based on their location and coverage requirements, providing targeted coverage enhancement where needed while maintaining low power consumption through reduced bandwidth operation.
3Adaptability or versatility
If off-center subchannels are allocated to MTC devices, then coexistence with traditional UEs is improved, but mapping complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the mapping relationship between off-center subchannels and PRBs before actual communication occurs. The network node determines and signals the subchannel allocation in advance, reducing the mapping complexity during actual data transmission by using pre-established mapping rules.
Data Source
AI summary
Embodiments described herein are directed methods and network nodes for operating a wireless device in a wireless network. The network node is configured to determine a subchannel within a system bandwidth of the wireless network. The subchannel is an off-center subchannel with respect to the system bandwidth, and the subchannel includes a plurality of consecutive subcarriers taken from one or more contiguous physical resource blocks. The network node can further map the subchannel's center frequency to a subcarrier of a physical resource block included in the subchannel, wherein the center frequency corresponds to a direct current subcarrier at a receiver associated with the wireless device. The network node can allocate the subchannel to the wireless device.