# US 9,438,396 B2 · Radio communication system, mobile terminal apparatus, radio base station apparatus and radio communication method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,438,396 B2 - Document ID: US9438396B2 - Status: Granted - Kind: B2 - Application number: 14/398,834 - Filed: 2013-04-24 - Published: 2015-05-14 - Granted: 2016-09-06 - Earliest claimed: 2012-05-10 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Yuichi Kakishima; Yoshihisa Kishiyama - Web page: https://patentgrep.com/patent/US9438396B2 ## CPC - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04J 13/0062: {Zadoff-Chu} - H04J 13/22: Allocation of codes with a zero correlation zone - H04L 27/2613: {Structure of the reference signals} - H04W 72/0466: {the resource being a scrambling code} - H04L 5/0023: {Time-frequency-space} - H04L 27/26134: {Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present invention is designed to allow more DM-RS sequences to be allocated, and more DM-RS resources to be secured. The radio communication method of the present invention has a characteristic of generating DM-RS sequences using ZC sequences that are allocated in a new number of randomized sequences between the number of randomized sequences corresponding to a ZC sequence having a length of the largest prime number, not exceeding the ZC sequence length required in the uplink DM-RS, and the number of randomized sequences defined in Rel. 10 LTE. ## Claims ### Claim 1 A radio communication system comprising a radio base station apparatus and a mobile terminal apparatus that is configured to be able to communicate with the radio base station apparatus, wherein: the radio base station apparatus comprises an allocation section configured to allocate Zadoff-Chu sequences in a new number of randomized sequences, the new number being a number between the number of randomized sequences corresponding to a Zadoff-Chu sequence having a length of a largest prime number, not exceeding a Zadoff-Chu sequence length required in an uplink demodulation reference signal, and the number of randomized sequences defined in Rel. 10 LTE, the mobile terminal apparatus comprises a generating section configured to generate demodulation reference signal sequences using the Zadoff-Chu sequences allocated in the new number of randomized sequences, and the number of randomized sequences defined in Rel. 10 LTE is set to 30 for bandwidth of 1 RB to 5 RBs, and is set to 60 for bandwidth of 6 RBs or more. ### Claim 2 (depends on 1) The radio communication system according to claim 1, wherein the new number of randomized sequences is set to a number selected from 30, 60 and at least one different number from 30 and 60. ### Claim 3 (depends on 1) The radio communication system according to claim 1, wherein the allocation section does not allocate the Zadoff-Chu sequences to a narrow transmission bandwidth. ### Claim 4 (depends on 1) The radio communication system according to claim 1, wherein the new number of randomized sequences is determined by combining a group number u and a base sequence number v that are used to generate the Zadoff-Chu sequences. ### Claim 5 (depends on 4) The radio communication system according to claim 4, wherein the radio base station apparatus reports the base sequence number v to the mobile terminal apparatus. ### Claim 6 (depends on 4) The radio communication system according to claim 4, wherein the radio base station apparatus reports a sequence number q that is used to generate the Zadoff-Chu sequences, to the mobile terminal apparatus. ### Claim 7 (depends on 4) The radio communication system according to claim 4, wherein the mobile terminal apparatus derives a sequence number q that is used to generate the Zadoff-Chu sequences, from an index signaled from the radio base station apparatus. ### Claim 8 (depends on 1) The radio communication system according to claim 1, wherein the radio base station apparatus reports a sequence number q that is used to generate the Zadoff-Chu sequences, to the mobile terminal apparatus. ### Claim 9 (depends on 1) The radio communication system according to claim 1, wherein the mobile terminal apparatus derives a sequence number q that is used to generate the Zadoff-Chu sequences, from an index signaled from the radio base station apparatus. ### Claim 10 A radio base station apparatus in a radio communication system comprising the radio base station apparatus and a mobile terminal apparatus that is configured to be able to communicate with the radio base station apparatus, the radio base station apparatus comprising: an allocation section configured to allocate Zadoff-Chu sequences in a new number of randomized sequences, the new number being a number between the number of randomized sequences corresponding to a Zadoff-Chu sequence having a length of a largest prime number, not exceeding a Zadoff-Chu sequence length required in an uplink demodulation reference signal, and the number of randomized sequences defined in Rel. 10 LTE, wherein the number of randomized sequences defined in Rel. 10 LTE is set to 30 for bandwidth of 1 RB to 5 RBs, and is set to 60 for bandwidth of 6 RBs or more. ### Claim 11 A mobile terminal apparatus in a radio communication system comprising a radio base station apparatus and the mobile terminal apparatus configured to be able to communicate with the radio base station apparatus, the mobile terminal apparatus comprising: a generating section configured to generate demodulation reference signal sequences using Zadoff-Chu sequences allocated in a new number of randomized sequences, the new number being a number between the number of randomized sequences corresponding to a Zadoff-Chu sequence having a length of a largest prime number, not exceeding a Zadoff-Chu sequence length required in an uplink demodulation reference signal, and the number of randomized sequences defined in Rel. 10 LTE, wherein the number of randomized sequences defined in Rel. 10 LTE is set to 30 for bandwidth of 1 RB to 5 RBs, and is set to 60 for bandwidth of 6 RBs or more. ### Claim 12 A radio communication method in a radio communication system comprising a radio base station apparatus and a mobile terminal apparatus that is configured to be able to communicate with the radio base station apparatus, the radio communication method comprising the steps of: in the radio base station apparatus, allocating Zadoff-Chu sequences in a new number of randomized sequences, the new number being a number between the number of randomized sequences corresponding to a Zadoff-Chu sequence having a length of a largest prime number, not exceeding a Zadoff-Chu sequence length required in an uplink demodulation reference signal, and the number of randomized sequences defined in Rel. 10 LTE; and in the mobile terminal apparatus, generating demodulation reference signal sequences using the Zadoff-Chu sequences allocated in the new number of randomized sequences, wherein the number of randomized sequences defined in Rel. 10 LTE is set to 30 for bandwidth of 1 RB to 5 RBs, and is set to 60 for bandwidth of 6 RBs or more.