Relay Station Group Forwarding Downlink Signals
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Solution Overview
Problem
In wireless communication systems, mobile stations (MS) covered by multiple relay stations (RSs) often experience low signal-to-noise ratios and communication rates due to path attenuation, failing to meet Quality of Service (QoS) requirements when the distance between RSs is great, leading to inefficient resource utilization.
Innovation Solution
A method where the base station (BS) determines an RS group based on downlink qualities and selects multiple RSs to forward downlink signals using space-time coding, allowing the MS to receive diverse signals simultaneously, thereby improving communication quality and meeting QoS requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single RS is selected to forward downlink data to an MS covered by multiple RSs, then the device complexity is reduced, but the receiving signal-to-noise ratio becomes low due to path attenuation, resulting in low communication rate that cannot satisfy QoS requirements
Solution Approach 1:
The patent merges the resources of multiple relay stations by forming an RS group that simultaneously forwards downlink data to the same MS. Instead of selecting a single RS, multiple RSs are combined to work together, where each RS transmits data on different time-frequency resources. This combining approach increases the communication rate and ensures QoS requirements are met while maintaining manageable system complexity through coordinated multi-RS operation.
2Productivity
If multiple RSs are used to forward downlink signals simultaneously, then the communication rate and QoS are improved through diversity gain, but the time-frequency resource allocation becomes more complex and resources may not be utilized efficiently
Solution Approach 1:
The patent segments the downlink data transmission by allocating different time-frequency resources to each RS in the RS group. Instead of having all RSs transmit on the same resources, the transmission resources are divided and distributed among multiple RSs. This segmentation allows multiple RSs to contribute to the same MS communication simultaneously, achieving diversity gain and higher communication rates while maintaining organized and manageable resource allocation through the segmented approach.
3Object-generated harmful factors
If RSs use orthogonal time-frequency resources when forwarding downlink services, then interference between RSs is prevented, but resource utilization efficiency decreases when an MS is covered by multiple RSs
Solution Approach 1:
The patent introduces dynamic resource allocation where the orthogonality of time-frequency resources between RSs is adjusted based on service requirements. For MSs covered by multiple RSs, the system dynamically allocates different time-frequency resources to each RS in the RS group, allowing non-orthogonal resource usage when beneficial. This dynamic approach prevents interference when needed while improving resource utilization efficiency when multiple RSs serve the same MS, moving away from static orthogonal allocation.
Data Source
AI summary
A method for relay stations (RSs) to forward downlink signals includes: obtaining downlink qualities between a mobile station (MS) and each of the RSs; determining an RS group for forwarding downlink signals according to difference degrees among all of the downlink qualities; performing space-time coding on the downlink signals through the RSs in the RS group when the RS group contains a plurality of RSs. Another method for RSs to forward downlink signals includes: setting the number of the RSs for forwarding the downlink signals to plurality; obtaining downlink qualities between an MS and each of the RSs; determining an RS group for forwarding the downlink signals according to each of the downlink qualities and the number of the RSs; performing space-time coding on the downlink signals through the RSs in the RS group, and forwarding the downlink signals to the MS. A device structure for the RSs to forward the downlink signals is also provided.