Patent ID: 8699364
Filing Date: 2014-04-15
Classification: H04B,H04J,H04W

Abstract:
1. A radio base station device applicable to a wireless communication system comprising the radio base station device (eNodeB) that controls communication with a radio terminal device (User Equipment) and a radio relay station device (Relay Node) that relays communication between the radio base station device and the radio terminal device, the radio base station device comprising: a preamble signal receiving unit that receives a random access preamble signal (RACH Preamble) transmitted from the radio terminal device, the radio terminal device comprising an RRC control unit that transmits, upon receiving a random access response signal transmitted from the radio base station device, an RRC connection request to the radio base station device, a best cell searching unit that searches, when an RRC connection by the RRC connection request fails, a best cell whose reception quality is the best, and a preamble signal transmitting unit that transmits, when a cell identifier of the best cell matches a cell identifier comprised in the random access response signal, the random access preamble signal comprising a random access identifier comprised in the random access response signal; a reception notice receiving unit that receives, from the radio relay station device, a reception notice indicating that the radio relay station device has received the random access preamble signal; and a response signal transmitting unit which permits, when a random access identifier (RA-ID) of a random access preamble signal transmitted from the radio terminal device matches a random access identifier comprised in the reception notice transmitted from the radio relay station device, the use of the matching random access identifier by the radio relay station device and transmits, to the radio terminal device, a random access response signal (RACH Response) comprising a cell identifier (Cell ID) of a cell managed by the radio relay station device permitted to use the random access identifier.