Frequency-First Control Channel Mapping for Relay Backhaul
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently mapping and managing control channels between base stations and relay nodes, particularly in frequency and time domains, which affects the reliability and efficiency of data transmission in relay-based networks.
Innovation Solution
The implementation of methods and apparatus for compatible mapping of control signals, including frequency-first mapping of control channel elements and tree-based relay resource allocation, to optimize the transmission of control signals between base stations and type I relay nodes, utilizing MBSFN-reserved sub-frames and specific encoding procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If control signals are mapped in time-first order, then the mapping process is simpler, but the decoding delay increases and reliability decreases
Solution Approach 1:
The patent inverts the conventional time-first mapping approach by implementing frequency-first mapping of control channel elements. Instead of mapping control signals sequentially in the time domain first, the system maps control channel elements across frequency resources first, then progresses through time. This inversion reduces decoding delay and improves reliability while maintaining manageable mapping complexity through systematic frequency-domain organization.
2Productivity
If relay nodes transmit and receive simultaneously in the same frequency band, then spectrum efficiency improves, but self-interference increases
Solution Approach 1:
The patent segments the frequency band into dedicated backhaul uplink and downlink frequency ranges. Relay nodes transmit in one frequency range while receiving in another, preventing simultaneous transmission and reception in the same band. This segmentation eliminates self-interference while maintaining spectrum efficiency through coordinated use of both frequency ranges for bidirectional communication.
3Adaptability or versatility
If control channel elements are mapped without frequency-first ordering, then resource allocation is more flexible, but mapping consistency and reliability decrease
Solution Approach 1:
The patent applies frequency-first mapping specifically to control channel elements while maintaining flexibility for data channel allocation. This localized application of structured mapping ensures consistent and reliable control signal transmission, while resource allocation for data remains adaptable. The frequency-first approach creates predictable patterns for control channels without constraining overall resource management flexibility.
Data Source
AI summary
Methods and apparatus are described for providing compatible mapping for backhaul control channels, frequency first mapping of control channel elements (CCEs) to avoid relay-physical control format indicator channel (R-PCFICH) and a tree based relay resource allocation to minimize the resource allocation map bits. Methods and apparatus (e.g., relay node (RN)/evolved Node-B (eNB)) for mapping of the Un downlink (DL) control signals, Un DL positive acknowledgement (ACK)/negative acknowledgement (NACK), and/or relay-physical downlink control channel (R-PDCCH) (or similar) in the eNB to RN (Un interface) DL direction are described. This includes time/frequency mapping of above-mentioned control signals into resource blocks (RBs) of multimedia broadcast multicast services (MBMS) single frequency network (MBSFN)-reserved sub-frames in the RN cell and encoding procedures for these. Also described are methods and apparatus for optimizing signaling overheads by avoiding R-PCFICH and minimizing bits needs for resource allocation.