Joint Precoding for Cellular D2D Spectrum Sharing
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Solution Overview
Problem
Current cellular and device-to-device (D2D) communication systems face inefficiencies in spectrum utilization due to the need for different spectrum resources, leading to reduced capacity and efficiency.
Innovation Solution
A method and apparatus for a mobile terminal with multiple antennas that superpose data for transmission to two devices, using a constructed data matrix to cancel interference and enable efficient transmission over shared resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cellular communication and D2D communication use different independent spectrum resources, then interference between transmissions is avoided, but spectrum utilization efficiency is reduced
Solution Approach 1:
The patent merges cellular communication and D2D communication into a unified transmission framework where both types of traffic share the same spectrum resources. The base station coordinates transmissions to multiple terminals (including both cellular and D2D devices) using joint precoding techniques, allowing simultaneous transmission over common resources while managing interference through signal processing.
Solution Approach 2:
The patent changes the transmission parameters by introducing joint precoding matrices that adaptively adjust signal characteristics for different terminal types. The base station dynamically modifies transmission parameters including power allocation, precoding weights, and resource assignment based on channel conditions and traffic requirements, enabling efficient shared spectrum utilization.
2Productivity
If the same time-frequency resource is used for cellular uplink and D2D communication, then spectrum utilization efficiency is enhanced, but interference between transmissions occurs
Solution Approach 1:
The patent converts the harmful interference effect into a beneficial signal by employing joint precoding where the base station intentionally designs transmission signals that account for interference patterns. The interference between cellular and D2D transmissions is transformed into constructive signal components through coordinated precoding, allowing the same time-frequency resources to be utilized by multiple terminals simultaneously without degradation.
3Productivity
If multiple terminals transmit data simultaneously over shared resources, then system capacity is increased, but interference cancellation complexity increases
Solution Approach 1:
The patent applies preliminary action by performing joint precoding at the base station before transmission. The base station calculates and applies precoding matrices that pre-compensate for potential interference between simultaneous transmissions to multiple terminals. This preliminary signal processing eliminates the need for complex post-reception interference cancellation at the terminals, reducing overall system complexity while maintaining high system capacity.
Data Source
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AI summary
Embodiments of the present invention disclose a signal transmitting and receiving method and apparatus. The signal transmitting method includes: constructing data for first antenna and data for second antenna, where the data for first antenna comprises first transmission data that needs to be transmitted to a first device, transmission data that needs to be transmitted to a second device, and a parameter of a transmission channel from a second antenna to the first device; and using the first antenna and the second antenna to transmit the data for first antenna and the data for second antenna to the first device and the second device respectively, so that the first device cancels interference caused by the transmission data that needs to be transmitted to the second device in the data for first antenna and the data for second antenna, to the first transmission data and the second transmission data. The present invention can superpose data directed to two terminals and then transmit the data, thereby enhancing system capacity and spectrum efficiency.