Orthogonal Pilot Substitution in Relay Stations
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Solution Overview
Problem
Conventional mobile communication systems face reduced system throughput due to interference from relay station signals, which deteriorate error rate characteristics and limit high transmission rates, especially in high-frequency radio bands where increased base station deployment is costly.
Innovation Solution
A radio communication method and apparatus that involves transmitting a first signal with a known pilot from a transmitting apparatus to a relay station, which substitutes an orthogonal known signal for the pilot in the signal addressed to the receiving apparatus, allowing the relay station to transmit the modified signal, thereby reducing interference and improving system throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a relay station apparatus is used to enlarge coverage area, then the coverage area is substantially enlarged, but the relayed radio signal becomes an interference signal to other radio signals, causing error rate deterioration and decreased system throughput
Solution Approach 1:
The patent converts the harmful interference signal from the relay station into a beneficial signal by making it orthogonal to the direct transmission signal. The relay station transmits the same signal as the base station using an orthogonal pilot sequence, transforming what was previously harmful interference into a signal that can be effectively separated and combined at the mobile station, thereby improving reception quality and system throughput while maintaining enlarged coverage area
2Speed
If base station apparatuses are increased to achieve high transmission rate over long distances, then high transmission rate is achieved, but the cost increases significantly
Solution Approach 1:
The relay station apparatus performs multiple functions: it extends coverage area, maintains high transmission rates, and reduces the need for additional base stations. By enabling the relay station to transmit signals that are orthogonal rather than interfering, the system achieves long-distance high-rate transmission with fewer infrastructure elements, as the relay station serves both coverage extension and capacity maintenance roles
Data Source
AI summary
A wireless communication method and the like for improving the system throughput. The wireless communication method is used in a mobile communication system having a base station apparatus (BS), a relay station apparatus (RS) (100) and a mobile station apparatus (MS) #1. In a first transmission step, a first transport signal, which includes data addressed to MS #1, is transmitted from BS to RS (100). In a second transmission step, a second transport signal, which includes a pilot generated by BS, is transmitted from BS. Simultaneously, in the second transmission step, a relay signal, which includes the data addressed to MS #1 and also includes a pilot that is generated by RS (100) and that has a particular orthogonal relationship with the pilot generated by BS, is transmitted from RS (100) to MS #1.