Uplink Resource Allocation for Low-Power MTC Devices
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Solution Overview
Problem
Current communication systems face challenges in optimizing coverage and capacity for machine-type communication (MTC) devices operating at decreased transmission power and bit rates, which can lead to network overload and interference with higher-value services.
Innovation Solution
The solution involves allocating specific uplink resources with reduced transmission power and bit rates for MTC devices, utilizing code division multiplexing and extending transmission over multiple subframes with an additional overlay cover code, to improve orthogonalization and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MTC devices operate at decreased transmission power and bit rate, then device cost and energy consumption are reduced, but network coverage and signal reliability deteriorate
Solution Approach 1:
The patent implements subframe repetition where MTC devices transmit the same data over multiple subframes (e.g., 4 or 8 repetitions). This periodic transmission allows the device to use lower transmission power per subframe while accumulating sufficient signal energy at the receiver over time, thereby maintaining coverage without increasing peak power consumption.
Solution Approach 2:
The patent creates multiple copies of the same data transmission across different subframes. Each subframe contains an identical copy of the uplink data, and the base station combines these copies to improve signal detection reliability. This copying approach enables low-power operation by distributing the transmission energy across multiple time instances.
2Productivity
If multiple MTC devices share the same uplink resources, then spectral efficiency is improved, but interference and collision between devices increase
Solution Approach 1:
The patent segments the uplink resources by introducing device-specific parameters that divide the shared resource space. Each MTC device is assigned a unique combination of cyclic shift values, orthogonal cover codes (OCC), and subframe repetition patterns. This segmentation allows multiple devices to transmit simultaneously on the same physical resources while maintaining orthogonality and minimizing interference.
Solution Approach 2:
The patent extends the multiplexing dimensions beyond traditional frequency and time domains by incorporating code domain resources. Devices are differentiated using cyclic shifts (phase domain), orthogonal cover codes (time-domain coding), and repetition patterns (temporal dimension). This multi-dimensional approach enables dense device multiplexing while maintaining signal separability at the base station.
3Reliability
If transmission time is extended to compensate for lower power, then coverage is improved, but transmission delay and resource occupancy increase
Solution Approach 1:
The patent uses periodic subframe repetition to extend transmission duration for coverage enhancement. However, it allows the base station to dynamically control the number of repetitions based on device capabilities and channel conditions. Devices can be configured with different repetition numbers (e.g., 1, 2, 4, or 8), enabling a trade-off between coverage and latency on demand.
Solution Approach 2:
The patent introduces dynamic adaptability where the transmission parameters (number of repetitions, cyclic shift, OCC) are not fixed but can be adjusted based on real-time network conditions, device power levels, and QoS requirements. This dynamic configuration allows the system to optimize the balance between coverage extension and transmission delay for each device individually.
Data Source
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AI summary
The invention relates to an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: allocate at least one specific uplink resource for uplink shared channel data to at least one device operable at decreased transmission power and/or bit rate, wherein the at least one specific uplink resource is at least one frequency resource and/or at least one time resource, and wherein the at least one specific uplink resource comprises a plurality of reference symbols, and if a plurality of devices are allocated, separate the devices on the at least one specific uplink resource by multiplexing, wherein the multiplexing comprises code division multiplexing.