# US 2014/0192756 A1 · Reference signal generation technique > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192756 A1 - Document ID: US20140192756A1 - Status: Published application - Kind: A1 - Application number: 14/236,187 - Filed: 2011-08-05 - Published: 2014-07-10 - Earliest claimed: 2011-08-05 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Robert Baldemair; Stefano Sorrentino - Web page: https://patentgrep.com/patent/US20140192756A1 ## CPC - H04L 27/2613: {Structure of the reference signals} - H04L 5/001: {the frequencies being arranged in component carriers} - H04L 5/0039: {Frequency-contiguous, i.e. with no allocation of frequencies for one user or terminal between the frequencies allocated to another} - 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)} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 5/0073: {Allocation arrangements that take into account other cell interferences} - H04L 5/0094: {Indication of how sub-channels of the path are allocated} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A technique for generating a reference signal for use in a communication system in which for reference signal generation multiple base sequences are defined is presented. A method implementation of the technique comprises generating a first reference signal sequence from a first base sequence and a second reference signal sequence from a second base sequence. A reference signal is generated that comprises the first reference signal sequence and the second reference signal sequence. The first reference signal sequence occupies a first spectral fragment of the reference signal, and the second reference signal sequence occupies a second spectral fragment of the reference signal. The second spectral fragment and the first spectral fragment do not overlap. ## Claims ### Claim 1 A method of generating a reference signal for use in a communication system in which for reference signal generation multiple base sequences are defined, the method comprising generating a first reference signal sequence from a first base sequence; generating a second reference signal sequence from a second base sequence; and generating a reference signal comprising the first reference signal sequence and the second reference signal sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap. ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining spectral information defining at least one of spectral sizes and spectral positions of the first spectral fragment and the second spectral fragment in a spectral bandwidth covered by the reference signal; and generating the reference signal taking into account the spectral information. ### Claim 3 (depends on 2) The method of claim 2, wherein the reference signal extends in a spectral dimension over at least one resource block, and the spectral information is defined by resource block indices. ### Claim 4 (depends on 2) The method of claim 2, wherein the spectral information is received in a resource allocation message that defines for a transmission channel of the reference signal at least one of a transmission channel bandwidth and a spectral position of the transmission channel. ### Claim 5 (depends on 1) The method of claim 1, wherein the reference signal has a spectral bandwidth that coincides with a transmission channel bandwidth that is used for data transmissions. ### Claim 6 (depends on 1) The method of claim 1, further comprising determining assignment information that assigns at least one of the first base sequence and the second base sequence to the respective spectral fragment. ### Claim 7 (depends on 6) The method of claim 6, wherein the assignment information is received in a resource allocation message that defines for a transmission channel of the reference signal at least one of a transmission channel bandwidth and a spectral position of the transmission channel. ### Claim 8 (depends on 1) The method of claim 1, wherein generating the first reference signal sequence and the second reference signal sequence comprises applying at least one of a cyclic shift and an orthogonal cover code to the first base sequence and the second base sequence, respectively. ### Claim 9 (depends on 1) The method of claim 1, wherein generating the first reference signal sequence and the second reference signal sequence comprises applying at least one of a sequence group hopping pattern and a sequence-within-group hopping pattern to determine the first base sequence and the second base sequence, respectively. ### Claim 10 (depends on 9) The method of claim 9, wherein the first reference signal sequence is associated with at least one of a first sequence group hopping pattern and a first sequence-within-group hopping pattern; and the second reference signal sequence is associated with at least one of a second sequence group hopping pattern and a second sequence group hopping pattern different from the first sequence hopping pattern and the first sequence group hopping pattern, respectively. ### Claim 11 (depends on 1) The method of claim 1, further comprising: generating at least a third reference signal sequence based on at least a third base sequence; and generating the reference signal from the first reference signal sequence, the second reference signal sequence, and the third reference signal sequence, wherein the third reference signal sequence occupies a third spectral fragment of the reference signal, and wherein the third spectral fragment does not overlap with the first spectral fragment and the second spectral fragment. ### Claim 12 A method of performing channel estimation based on a reference signal in a communication system in which for reference signal generation multiple base sequences are defined, the method comprising receiving a reference signal comprising a first reference signal sequence generated from a first base sequence and a second reference signal sequence generated from a second base sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, and the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap; and performing channel estimation based on the received reference signal and based on at least one of the first reference signal sequence and the second reference signal sequence. ### Claim 13 (depends on 12) The method of claim 12, wherein channel estimation comprises a matched filtering of the received reference signal, wherein the matched filtering is based on at least one of the first reference signal sequence and the second reference signal sequence. ### Claim 14 (depends on 12) The method of claim 12, further comprising: allocating at least one of spectral sizes and spectral positions to the first spectral fragment and the second spectral fragment; and transmitting spectral information indicative of the spectral allocation to a reference signal generator. ### Claim 15 (depends on 14) The method of claim 14, wherein the spectral information is transmitted via at least one scheduling grant. ### Claim 16 (depends on 12) The method of claim 12, further comprising assigning at least one of the first base sequence and the second base sequence to the respective spectral fragment; and transmitting assignment information indicative of the sequence assignment to a reference signal generator. ### Claim 17 (depends on 16) The method of claim 16, wherein the sequence assignment is performed semi-statically. ### Claim 18 (depends on 12) The method of claim 12, further comprising transmitting a control instruction to a reference signal generator, wherein the control instruction instructs the reference signal generator to switch from regular reference signalling in which the reference signal is generated from a single reference signal sequence to enhanced reference signalling in which the reference signal is generated from the first reference signal sequence and the second reference signal sequence. ### Claim 19 (depends on 12) The method of claim 12, further comprising co-scheduling a transmitter of a fragmented reference signal and a transmitter of a non-fragmented reference signal on at least partly overlapping transmission bandwidths, wherein the non-fragmented reference signal comprises a single reference signal sequence that has been generated from one of the first base sequence and the second base sequence. ### Claim 20 A computer program product comprising program code portions for generating a reference signal for use in a communication system in which for reference signal generation multiple base sequences are defined, when the computer program product is executed on a computing device, the computing device: generates a first reference signal sequence from a first base sequence; generates a second reference signal sequence from a second base sequence; and generates a reference signal comprising the first reference signal sequence and the second reference signal sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, the second spectral fragment and the first spectral fragment do not overlap. ### Claim 21 (depends on 20) The computer program product of claim 20, wherein the computer program product is stored on a computer readable recording medium. ### Claim 22 An apparatus for generating a reference signal for use in a communication system in which for reference signal generation multiple base sequences are defined, the apparatus comprising: a sequence generator configured to generate a first reference signal sequence from a first base sequence and a second reference signal sequence from a second base sequence; and a reference signal generator configured to generate a reference signal comprising the first reference signal sequence and the second reference signal sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, and the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the apparatus is part of a user terminal. ### Claim 24 An apparatus for performing channel estimation based on a reference signal in a communication system in which for reference signal generation multiple base sequences are defined, the apparatus comprising: a receiver configured to receive a reference signal comprising a first reference signal sequence generated from a first base sequence and a second reference signal sequence generated from a second base sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, and the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap; and a channel estimator configured to perform channel estimation based on the received reference signal and based on at least one of the first reference signal sequence and the second reference signal sequence. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the apparatus is part of a base station. ### Claim 26 A communication system comprising: at least one of an apparatus and a user terminal for generating a reference signal for use in the communication system in which for reference signal generation multiple base sequences are defined, the at least one of the apparatus and the user terminal including: a sequence generator configured to generate a first reference signal sequence from a first base sequence and a second reference signal sequence from a second base sequence; and a reference signal generator configured to generate a reference signal comprising the first reference signal sequence and the second reference signal sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, and the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap; and at least one of a second apparatus and a base station for performing channel estimation based on a reference signal in a communication system in which for reference signal generation multiple base sequences are defined, the at least one of the second apparatus and the base station including: a receiver configured to receive a reference signal comprising a first reference signal sequence generated from a first base sequence and a second reference signal sequence generated from a second base sequence, the first reference signal sequence occupies a first spectral fragment of the reference signal and the second reference signal sequence occupies a second spectral fragment of the reference signal, and the second spectral fragment and the first spectral fragment are spectrally located immediately adjacent to one another and do not spectrally overlap; and a channel estimator configured to perform channel estimation based on the received reference signal and based on at least one of the first reference signal sequence and the second reference signal sequence. ### Claim 27 (depends on 26) The communication system of claim 26, wherein the communication system is configured to operate in accordance with one of Long Term Evolution Release 10 and 11.