PDCCH Capacity Enhancement via Orthogonal Code Multiplexing
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Solution Overview
Problem
Conventional PDCCH beamforming in cellular communications is limited to a single PDCCH per UE, preventing the utilization of multiple PDCCHs to enhance capacity.
Innovation Solution
Communicating a first PDCCH and a second PDCCH in a single OFDM symbol of a subframe, allowing the remaining PDCCH code space to be used for data transmission by multiplying the second PDCCH with an orthogonal code, enabling the UE to distinguish between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single PDCCH is transmitted per UE in conventional beamforming, then the transmission structure remains simple, but the PDCCH capacity is limited
Solution Approach 1:
The PDCCH transmission is segmented into multiple PDCCH instances (first PDCCH and second PDCCH) within the same OFDM symbol. Each PDCCH is assigned different orthogonal codes and code space resources, enabling multiple control channels to coexist in a single transmission slot without interfering with each other, thus increasing PDCCH capacity while maintaining manageable complexity through structured resource division
Solution Approach 2:
The patent introduces a new dimension for PDCCH differentiation by using code space and orthogonal codes instead of solely relying on time or frequency separation. By assigning PDCCHs to different code spaces within the same OFDM symbol, the system effectively adds a code domain dimension to the transmission structure, enabling increased capacity without proportionally increasing time-frequency resource usage
2Productivity
If multiple PDCCHs are transmitted in the same OFDM symbol, then PDCCH capacity increases, but the UE must distinguish between them using orthogonal codes
Solution Approach 1:
Orthogonal codes serve as intermediaries between multiple PDCCH transmissions and the UE receiver. These codes enable the UE to distinguish and separately decode multiple PDCCHs transmitted in the same OFDM symbol by correlating the received signal with different orthogonal code sequences, thus facilitating efficient multi-PDCCH detection without increasing difficulty
3Quantity of substance
If the entire PDCCH code space is utilized for data transmission, then resource utilization improves, but control channel capacity must be maintained
Solution Approach 1:
The code space is segmented into distinct allocations for control and data purposes. Specific code resources are reserved for PDCCH transmissions (enabling multiple control channels through orthogonal coding), while the remaining code space is allocated for data transmission. This segmentation ensures that control channel reliability is maintained through dedicated resources while maximizing overall code space utilization for data
Data Source
AI summary
Systems and methods are provided for enhancing physical downlink control channel (PDCCH) capacity. To do so, a first PDCCH and a second PDCCH are communicated in single orthogonal frequency division multiplexing (OFDM) symbol of a subframe, freeing the remainder of the PDCCH code space for data. Initially, a transmission is communicated, by a node configured to wirelessly communicate with a user equipment (UE), to the UE. The transmission includes a first PDCCH in a first OFDM symbol of a subframe. The transmission also includes a second PDCCH in the first OFDM symbol of the subframe.