Virtual Cell Identity for Distributed Antenna Multipoint Transmission
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently communicating using multiple points within the same cell or with different physical cell identities, particularly in CoMP transmission environments where existing standards are not applicable.
Innovation Solution
The implementation of a wireless communication method that assigns virtual cell identities and initializes pseudo-random sequences for terminals, allowing for efficient uplink and downlink communication by configuring base sequences and cyclic shift hopping for demodulation reference signals, and providing information on cell-specific reference signal energy per resource element to terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple transmission points use different physical cell identities (PCIs) as per existing standards, then each TP has its own cell coverage and standard compliance is maintained, but efficient multipoint transmission within the same cell cannot be achieved
Solution Approach 1:
The patent segments the cell identity concept into two parts: physical cell identity (PCI) for cell-level identification and virtual cell identity (VCI) for point-level identification. This allows multiple TPs to share the same PCI while having distinct VCIs, enabling multipoint transmission within a single cell without violating standard compliance.
Solution Approach 2:
The patent introduces virtual cell identity (VCI) as an intermediary layer between the physical cell identity and the transmission points. The VCI acts as a mediator that enables differentiation among multiple TPs within the same cell, allowing efficient multipoint transmission while maintaining the unified cell structure required by existing standards.
2Productivity
If joint processing is used in downlink CoMP transmission, then accurate wireless channel information is required, but performance varies with delay and estimation error
Solution Approach 1:
The patent performs preliminary channel estimation and reference signal configuration at the base station before actual data transmission. By pre-configuring the reference signals with appropriate VCIs and estimating channels in advance, the system reduces the impact of delay and estimation errors during actual transmission, improving both productivity and reliability.
Solution Approach 2:
The patent implements feedback mechanisms where channel state information is continuously monitored and reported. This feedback allows the base station to adjust transmission parameters dynamically, compensating for channel variations and estimation errors, thereby maintaining stable performance while achieving high data rates.
3Ease of operation
If dynamic point selection is used in downlink CoMP transmission, then one point performs PDSCH transmission, but performance deteriorates due to feedback delay
Solution Approach 1:
The patent enables dynamic selection of transmission points using virtual cell identities. The base station can dynamically switch between multiple TPs based on channel conditions, user location, and load distribution. This dynamic approach maintains transmission efficiency while keeping control operations simple through standardized VCI-based signaling.
4Reliability
If coordinated beamforming is used to avoid interference between TPs, then a passive method is employed, but large capacity increase cannot be expected
Solution Approach 1:
The patent changes the identification parameter from PCI to VCI, enabling active coordination among multiple TPs. By using VCIs, the system can dynamically adjust transmission parameters such as power allocation, resource block assignment, and beamforming vectors, transforming the passive interference avoidance approach into an active capacity enhancement mechanism.
Data Source
AI summary
Provided are a wireless communication system and method using distributed antennas. A physical channel and reference signal (RS) transmission/reception method for downlink and uplink communication using a plurality of points is provided for a case in which the plurality of points have different physical cell identities (PCIs), or in a wireless communication environment using distributed antennas in which the plurality of points belong to the same cell and have the same PCI. Also, a method of transmitting a physical channel and an RS in an uplink and a downlink by introducing a virtual cell identity (VCI) is provided. Further, a cooperative transmission method using a plurality of points is provided, so that communication efficiency of a wireless communication system using distributed antennas can be improved.