Relay Station Backhaul Link Control Channel Reception
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Solution Overview
Problem
In wireless communication systems, relay stations face challenges in receiving data from base stations due to differences in OFDM symbol sizes between the control channels transmitted to user equipment and relay stations, leading to improper reception of control channels and data.
Innovation Solution
A method and apparatus for a relay station to receive data by providing radio resource allocation information that includes both frequency domain and time domain allocations, using R-PDCCH and R-PDSCH channels, ensuring accurate synchronization and resource allocation for reliable data reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relay station uses the conventional LTE method for receiving control signals, then the user equipment can properly receive PDCCH through PCFICH indicating OFDM symbol allocation, but the relay station cannot properly receive PDCCH because the OFDM symbol sizes differ between backhaul link and access link
Solution Approach 1:
The patent segments the control channel reception process by introducing a separate R-PDCCH for the backhaul link with its own dedicated PCFICH (R-PCFICH). This allows the backhaul link control channel to be independently configured and indicated, separate from the access link PDCCH, thereby resolving the conflict caused by different OFDM symbol size requirements between the two links.
Solution Approach 2:
The patent introduces R-PCFICH as an intermediary channel that carries control format indicator information specifically for the backhaul link. This intermediary provides the relay station with the necessary information about R-PDCCH OFDM symbol allocation, acting as a mediator between the base station's transmission and the relay station's reception requirements.
2Device complexity
If the base station transmits control information only in frequency domain through PDCCH, then the implementation is simple, but the relay station cannot determine the time domain allocation of OFDM symbols for proper signal reception
Solution Approach 1:
The patent applies preliminary action by transmitting the control format indicator information through R-PCFICH before the actual R-PDCCH transmission. This allows the relay station to know in advance the number of OFDM symbols allocated for R-PDCCH, enabling proper reception preparation without adding complex time domain allocation mechanisms to the PDCCH itself.
Solution Approach 2:
The patent extends the control information transmission from only frequency domain (PDCCH resource block allocation) to include time dimension by introducing R-PCFICH that indicates OFDM symbol allocation. This adds the time dimension to control channel resource indication, enabling precise time domain resource allocation for the backhaul link.
Data Source
AI summary
A method for receiving data by a relay station (RS) in a wireless communication system includes: receiving radio resource allocation information via an R-PDCCH (R-Physical Downlink Control Channel); and receiving data from a base station (BS) via an R-PDSCH (R-Physical Downlink Shared Channel) indicated by the radio resource allocation information, wherein the radio resource allocation information includes information regarding an allocation of resource blocks in a frequency domain and information regarding an allocation of OFDM symbols in a time domain. Since the radio resource allocation information providing information regarding a time relationship between a control channel transmitted by the BS to a UE and a control channel transmitted by the RS to a UE connected to the RS is provided, the RS can reliably receive a signal transmitted from the BS in a backhaul link between the BS and the RS in a wireless communication system including the RS.