# US 9,883,324 B2 · Methods and devices for sending and receiving location information for wireless devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,883,324 B2 - Document ID: US9883324B2 - Status: Granted - Kind: B2 - Application number: 13/388,579 - Filed: 2011-12-20 - Published: 2013-06-20 - Granted: 2018-01-30 - Earliest claimed: 2011-12-20 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Yngve Selén; Erik Dahlman; Stefan Parkvall; Markus Ringström - Inventors: Yngve Selén; Erik Dahlman; Stefan Parkvall; Markus Ringström - Web page: https://patentgrep.com/patent/US9883324B2 ## CPC - H04L 5/0033: {each allocating device acting autonomously, i.e. without negotiation with other allocating devices} - H04W 4/02: Services making use of location information - G06F 21/606: {by securing the transmission between two devices or processes} - H04L 63/0428: {wherein the data content is protected, e.g. by encrypting or encapsulating the payload} - H04W 4/029: Location-based management or tracking services - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 4/20: Services signaling; Auxiliary data signalling, i.e. transmitting data via a non-traffic channel - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - H04W 8/005: {Discovery of network devices, e.g. terminals} - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract The embodiments herein relate to a method in a first device (101) for informing a second device (105) that an identity associated with the first device (101) is at a certain location. The first device (101) obtains information about the location of the first device (101). The first device (101) broadcasts, by means of device to device, D2D, communication, a message to be received by the second device (105). The message comprises the location information and an identity information associated with a user of the first device (101). The location information is transmitted on a first communications resource and the identity information is transmitted on a second communications resource. ## Claims ### Claim 1 A method in a first device for informing a second device that an identity associated with the first device is at a certain location, the method comprising: obtaining information about the location of the first device; determining a second communications resource using a hash function, wherein the hash function has as input an identifier of a first communications resource; and broadcasting, via a device to device (D2D) communication, a message to be received by the second device, wherein the message includes the location information and identity information that identifies a user of the first device, and wherein the identity information is transmitted on the first communications resource and the location information is transmitted on the second communications resource. ### Claim 2 (depends on 1) The method of claim 1, further comprising: obtaining a number of data bits based on a coverage distance of the broadcasting of the message and based on a predefined precision of the location information; and truncating the location information to the obtained number of bits by discarding one or more most significant bits of the location information until the truncated location information has the obtained number of bits; and wherein the location information comprised in the message is the truncated location information. ### Claim 3 (depends on 2) The method of claim 2, wherein the number of data bits is predefined in the first device. ### Claim 4 (depends on 1) The method of claim 1, wherein the obtained location information is associated with a reference known to the first device and the second device. ### Claim 5 (depends on 4) The method of claim 4, wherein the reference is associated with a global positioning system, referred to as GPS, a local coordinate system or a global coordinate system. ### Claim 6 (depends on 1) The method of claim 1, further comprising: identifying an amount of available communications resources for the broadcasting of the message; and determining that the location information should be included in the message only when the identified amount of available communications resources is above a threshold. ### Claim 7 (depends on 1) The method of claim 1, further comprising: determining that the location information should be encrypted such that it can be decrypted by the second device; encrypting the location information by using an encryption key known to the first device; and wherein the location information included in the message is the encrypted location information. ### Claim 8 (depends on 1) The method of claim 1, wherein the first communications resource comprises an indication indicating that the message includes the location information. ### Claim 9 (depends on 1) The method of claim 1, wherein the first communications resource and the second communications resource are the same communications resource. ### Claim 10 (depends on 1) The method of claim 1, wherein the first communications resource and the second communications resource are different communications resources. ### Claim 11 (depends on 1) The method of claim 1, wherein the hash function is a hash function of both the identity information and the first communications resource. ### Claim 12 (depends on 11) The method of claim 11, wherein the first communications resource used to determine the second communications resource corresponds to at least one of an area in a time-frequency grid, a code, and a time slot of spectrum used by the first communication resource. ### Claim 13 A method in a second device for being informed by a first device that an identity associated with the first device is at a certain location, the method comprising: receiving, via a device to device (D2D) communication, a first portion of a message broadcast from the first device, wherein the first portion of the message includes identity information that identifies a user of the first device, wherein the identity information is received on a first communications resource; determining the second communications resource using a hash function, wherein the hash function has as input an identifier of the first communications resource; identifying that the location information is mapped to the determined second communications resource; and receiving, via a device to device (D2D) communication, a second portion of the message broadcast from the first device, wherein the second portion of the message includes information about the location of the first device, wherein the location information is received on the second communications resource. ### Claim 14 (depends on 13) The method of claim 13, further comprising detecting that the message includes the location information. ### Claim 15 (depends on 14) The method of claim 14, wherein the detecting that the message includes the location information further comprises: detecting an indication indicating that the message includes the location information, wherein the indication is comprised in the first communications resource. ### Claim 16 (depends on 13) The method of claim 13, wherein the location information in the message is encrypted by the first device using an encryption key known to the first device, and wherein the method further comprises decrypting the location information using a decryption key associated with the encryption key. ### Claim 17 (depends on 13) The method of claim 13, wherein the location information included in the message is truncated based on a coverage distance of the broadcasting of the message and a predefined precision of the location information, said truncated location information having most significant bits of original location information omitted. ### Claim 18 (depends on 13) The method of claim 13, wherein the location information is associated with a reference predefined in the second device and the first device. ### Claim 19 (depends on 18) The method of claim 18, wherein the reference is associated with a global positioning system, referred to as GPS, a local coordinate system or a global coordinate system. ### Claim 20 (depends on 18) The method of claim 18, further comprising: identifying the reference with which the location information is associated; and detruncating the truncated location information, based on the identified reference, by adding most significant bits to the truncated location information. ### Claim 21 (depends on 13) The method of claim 13, wherein the first communications resource and the second communications resource are the same communications resource. ### Claim 22 (depends on 13) The method of claim 13, wherein the hash function is a hash function of both the identity information and the first communications resource. ### Claim 23 A first device for informing a second device that an identity associated with the first device is at a certain location, the first device comprising: an obtaining unit configured to obtain information about the location of the first device; a determining unit configured to determine a second communications resource using a hash function, wherein the hash function has as input an identifier of a first communications resource; and a broadcasting unit configured to broadcast via a device to device (D2D) communication, a message to be received by the second device, wherein the message includes the location information and identity information that identifies a user of the first device, and wherein the identity information is transmitted on the first communications resource and the location information is transmitted on the second communications resource. ### Claim 24 (depends on 23) The first device of claim 23, wherein the obtaining unit is further configured to obtain a number of data bits based on a coverage distance of the message and a predefined precision of the location information; and wherein the first device further comprises: a truncating unit configured to truncate the location information to the obtained number of bits by discarding one or more most significant bits of the location information until the truncated location information has the obtained number of bits; and wherein the location information included in the message is the truncated location information. ### Claim 25 (depends on 24) The first device of claim 24, wherein the number of data bits is predefined in the first device. ### Claim 26 (depends on 23) The first device of claim 23, wherein the obtained location information is associated with a reference predefined in the first device and second device. ### Claim 27 (depends on 26) The first device of claim 26, wherein the reference is associated with a global positioning system, referred to as GPS, a local coordinate system or a global coordinate system. ### Claim 28 (depends on 23) The first device of claim 23, further comprising: an identifying unit configured to identify an amount of available communications resources for the broadcasting of the message; and a determining unit configured to determine that the location information should be included in the message only when the amount of available communications resources is above a threshold. ### Claim 29 (depends on 23) The first device of claim 23, further comprising: a determining unit configured to determine that the location information should be encrypted such that it can be decrypted by the second device; and an encrypting unit configured to encrypt the location information by using an encryption key known to the first device; and wherein the location information included in the message is the encrypted location information. ### Claim 30 (depends on 23) The first device of claim 23, wherein the first communications resource comprises an indication indicating that the message includes the location information. ### Claim 31 (depends on 23) The first device of claim 23, wherein the first communications resource and the second communications resource are the same communications resource. ### Claim 32 (depends on 23) The first device of claim 23, wherein the hash function is a hash function of both the identity information and the first communications resource. ### Claim 33 A second device for being informed by a first device that an identity associated with the first device is at a certain location, the second device comprising: a receiving unit configured to receive a message broadcast via a device to device (D2D) communication, from the first device, wherein the message includes information about the location of the first device and identity information that identifies a user of the first device, wherein the identity information is received on a first communications resource and the location information is received on a second communications resource; a determining unit configured to determine the second communications using a hash function, wherein the hash function has as input an identifier of the first communications resource; and an identifying unit configured to identify that the location information is mapped to the determined second communications resource. ### Claim 34 (depends on 33) The second device of claim 33, further comprising: a detecting unit configured to detect that the message includes the location information. ### Claim 35 (depends on 34) The second device of claim 34, wherein the detecting unit is further configured to detect an indication indicating that the message includes the location information, wherein the indication is comprised in the first communications resource. ### Claim 36 (depends on 33) The second device of claim 33, wherein the location information in the message is encrypted by the first device using an encryption key known to the first device, and wherein the second device further comprises: a decrypting unit configured to decrypt the location information using a decryption key associated with the encryption key. ### Claim 37 (depends on 33) The second device of claim 33, wherein the location information comprised in the message is truncated based on coverage distance of the broadcasting of the message and a desired precision of the location information, said truncated location information having most significant bits of original location information omitted. ### Claim 38 (depends on 33) The second device of claim 33, wherein the location information is associated with a reference predefined in the second device and the first device. ### Claim 39 (depends on 38) The second device of claim 38, wherein the reference is associated with a global positioning system, referred to as GPS, a local coordinate system or a global coordinate system. ### Claim 40 (depends on 38) The second device of claim 38, further comprising: an identifying unit configured to identify the reference with which the location information is associated; and a processing unit configured to detruncate the truncated location information, based on the identified reference, by adding most significant bits to the truncated location information. ### Claim 41 (depends on 33) The second device of claim 33, wherein the first communications resource and the second communications resource are the same communications resource. ### Claim 42 (depends on 33) The first device of claim 33, wherein the hash function is a hash function of both the identity information and the first communications resource.