# US 9,882,614 B2 · Wireless signal transmitting method and wireless apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,882,614 B2 - Document ID: US9882614B2 - Status: Granted - Kind: B2 - Application number: 14/375,037 - Filed: 2013-02-04 - Published: 2014-12-25 - Granted: 2018-01-30 - Earliest claimed: 2012-02-06 - Assignees: Nippon Telegraph and Telephone Corporation - Applicants: Nippon Telegraph and Telephone Corporation - Inventors: Tomoki Murakami; Yusuke Asai; Riichi Kudo; Koichi Ishihara; Masato Mizoguchi; Takeo Ichikawa - Web page: https://patentgrep.com/patent/US9882614B2 ## CPC - H04L 27/2613: {Structure of the reference signals} - H04B 7/024: Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems - H04B 7/0452: Multi-user MIMO systems - H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting - H04B 7/0617: {for beam forming} - H04J 11/0053: {using co-ordinated multipoint transmission/reception (co-ordinated antenna or beam-forming aspects H04B7/022)} - H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals} - H04W 28/16: Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service] - H04W 88/08: Access point devices - H04L 5/0035: {Resource allocation in a cooperative multipoint environment} - H04L 27/2626: {Arrangements specific to the transmitter only} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION - 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 Interference in preamble signals and pilot signals in cooperative transmission using interference suppressing technology is avoided. A wireless apparatus for transmitting a wireless signal on which directivity control has been performed to stations in a wireless system including at least one wireless apparatus is provided with a known signal generating unit which generates a known signal to be added to the wireless signal, a weighting processing unit which performs weighting on the known signal generated by the known signal generating unit, and a wireless processing unit which transmits the known signal on which the weighting has been performed by the weighting processing unit. ## Claims ### Claim 1 A wireless signal transmitting method in which at least one access point among a plurality of access points each constituting a different communication cell transmits a wireless signal on which directivity control has been performed to stations, the wireless signal transmitting method comprising: generating a preamble signal to be added to the wireless signal, the preamble signal being used to perform timing synchronization and frequency synchronization; generating a pilot subcarrier signal that is used to correct a residual frequency error; performing weighting on a data signal to which the pilot subcarrier signal has been added and outputting a wireless signal; extracting a propagation channel corresponding to a subcarrier in which the preamble signal is transmitted from among propagation channels acquired from the stations; calculating a weight based on the extracted propagation channel and performing weighting on the preamble signal; and transmitting the wireless signal on which the weighting has been performed and the preamble signal on which the weighting has been performed which is added to the wireless signal on which the weighting has been performed. ### Claim 2 (depends on 1) The wireless signal transmitting method according to claim 1, wherein, said weighting performed on the preamble signal is performed using a weighted preamble signal that is pre-calculated by multiplying the preamble signal by the weight calculated based on the propagation channel corresponding to the subcarrier in which the preamble signal is transmitted, and in the wireless processing step, the weighted preamble signal is added to the wireless signal and transmitted. ### Claim 3 (depends on 2) The wireless signal transmitting method according to claim 2, further comprising storing the pre-calculated weighted preamble signal, wherein, at a predetermined transmission timing, the weighted preamble signal stored in the storing step is read, and the read weighted preamble signal is added to the wireless signal and transmitted. ### Claim 4 A wireless apparatus which transmits a wireless signal on which directivity control has been performed to stations in a wireless system including a plurality of wireless apparatuses each constituting a different communication cell, the wireless apparatus comprising: a preamble signal generator which outputs a preamble signal to be added to the wireless signal, the preamble signal being used to perform timing synchronization and frequency synchronization; a pilot subcarrier signal generator which outputs a pilot subcarrier signal that is used to correct a residual frequency error; a weighting processor programmed to perform weighting on a data signal to which the pilot subcarrier signal has been added and programmed to output a wireless signal; an extraction circuit which extracts a propagation channel corresponding to a subcarrier in which the preamble signal is transmitted from among propagation channels acquired from the stations; a preamble signal weighting processor programmed to calculate a weight based on the propagation channel extracted by the extraction circuit and programmed to perform the weighting on the preamble signal using the weight; and a wireless transmitter which transmits the wireless signal on which the weighting has been performed and the preamble signal on which the weighting has been performed which is added to the wireless signal on which the weighting has been performed. ### Claim 5 (depends on 4) The wireless apparatus according to claim 4, wherein the preamble signal weighting processor pre-calculates a weighted preamble signal by multiplying the preamble signal by the weight calculated based on the propagation channel corresponding to the subcarrier in which the preamble signal is transmitted, and the wireless transmitter adds the weighted preamble signal to the wireless signal and performs transmission. ### Claim 6 (depends on 5) The wireless apparatus according to claim 5, further comprising a preamble storing memory which stores the weighted preamble signal pre-calculated by the preamble signal weighting processor, wherein, at a predetermined transmission timing, the wireless transmitter reads the weighted preamble signal stored in the memory, adds the read weighted preamble signal to the wireless signal, and performs transmission. ### Claim 7 A wireless signal transmitting method in which an access point transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules, the wireless signal transmitting method comprising: generating L-STF as a known signal; performing weighting on all input signals starting from L-LTF; and transmitting a transmission signal in which the known signal has been added to the input signals on which the weighting has been performed. ### Claim 8 (depends on 7) The wireless signal transmitting method according to claim 7, further comprising: calculating weight coefficients for part of subcarriers based on propagation channel information provided from the first receiving station and the second receiving station; and calculating weight coefficients of the remaining subcarriers based on the weight coefficients for the part of the subcarriers, wherein, the weighting is performed based on the weight coefficients calculated in the weight calculating step and the weight coefficients calculated in the weight interpolating step. ### Claim 9 (depends on 8) The wireless signal transmitting method according to claim 8, further comprising first transmitting between the first receiving station and the second receiving station a response signal from a receiving station configured to apply said first set of rules. ### Claim 10 A wireless signal transmitting method in which an access point transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules, the wireless signal transmitting method comprising: generating, as a common signal, L-STF, L-LTF, L-SIG, HT-SIG, and a pilot subcarrier signal; performing weighting on all input signals starting from VH-SIG-A excluding the pilot subcarrier signal; and transmitting a transmission signal in which the common signal is added to the input signals on which the weighting has been performed. ### Claim 11 (depends on 10) The wireless signal transmitting method according to claim 10, further comprising first transmitting between the first receiving station and the second receiving station a response signal from a receiving station configured to apply said first set of rules. ### Claim 12 A wireless signal transmitting method in which an access point transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules, the wireless signal transmitting method comprising: generating, as a known signal, L-STF and a pilot subcarrier signal; performing weighting on all input signals starting from L-LTF excluding the pilot subcarrier signal; and transmitting a transmission signal in which the known signal has been added to the input signals on which the weighting has been performed. ### Claim 13 (depends on 12) The wireless signal transmitting method according to claim 12 further comprising first transmitting between the first receiving station and the second receiving station a response signal from a receiving station configured to apply said first set of rules. ### Claim 14 A wireless apparatus which transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules, the wireless apparatus comprising: a signal generator which outputs L-STF as a known signal; a weighting processor programmed to perform weighting on all input signals starting from L-LTF; and a wireless transmitter which transmits a transmission signal in which the known signal is added to the input signals on which the weighting has been performed by the weighting processor. ### Claim 15 (depends on 14) The wireless apparatus according to claim 14, further comprising: a weight calculating processor programmed to calculate weight coefficients for part of subcarriers based on propagation channel information provided from the first receiving station and the second receiving station; and a weight interpolating processor programmed to calculate weight coefficients of the remaining subcarriers based on the weight coefficients for the part of the subcarriers, and the weighting processor is programmed to perform the weighting based on the weight coefficients calculated by the weight calculating processor and the weight coefficients calculated by the weight interpolating processor. ### Claim 16 A wireless apparatus which transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules in a wireless system including at least one wireless apparatus, the wireless apparatus comprising: a common signal generator which generates, as a common signal, L-STF, L-LTF, L-SIG, HT-SIG, and a pilot subcarrier signal; a weighting processor programmed to perform weighting on all input signals starting from VH-SIG-A excluding the pilot subcarrier signal; and a wireless transmitter which transmits a transmission signal in which the common signal is added to the input signals on which the weighting has been performed by the weighting processor. ### Claim 17 A wireless apparatus which transmits a wireless signal on which spatial division multiplexing has been performed to a first receiving station configured to apply a first set of rules defining transmissions and a second receiving station configured to apply a second set of rules defining transmissions that include transmissions not supported by the first set of rules in a wireless system including at least one wireless apparatus, the wireless apparatus comprising: a signal generator which outputs, as a known signal, L-STF and a pilot subcarrier signal; a weighting processor programmed to perform weighting on all input signals starting from L-LTF excluding the pilot subcarrier signal; and a wireless transmitter which transmits a transmission signal in which the known signal is added to the input signals on which the weighting has been performed by the weighting processor.