# US 2014/0153661 A1 · Method of Coding Using Multiple Transmit Chains for Reduced Exposure to Electromagnetic Radiation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153661 A1 - Document ID: US20140153661A1 - Status: Published application - Kind: A1 - Application number: 14/173,849 - Filed: 2014-02-06 - Published: 2014-06-05 - Earliest claimed: 2012-04-06 - Assignees: Bertrand M. Hochwald - Inventors: Bertrand Martyn Hochwald - Web page: https://patentgrep.com/patent/US20140153661A1 ## CPC - H04B 7/0465: {taking power constraints at power amplifier or emission constraints, e.g. constant modulus, into account} - H04B 7/0617: {for beam forming} - H04B: TRANSMISSION ## Abstract Embodiments of methods and apparatuses for transmission from an electromagnetic signal transmitting device utilizing a plurality of transmit chains based on a code that reduces exposure to electromagnetic radiation. One method is utilizing a plurality of chains, adjusting at least one of a phase or an amplitude of at least one of the transmit chains based on a code, wherein the codebook of code words is generated using at least one parameter that characterizes the electromagnetic radiation intensity, and wherein the number of code words satisfies a criterion for quality of reception at an intended receiver, and wherein the code words are selected, during operation of the transmitting device, in response to data that are to be transmitted. ## Claims ### Claim 1 A method of transmission from an electromagnetic signal transmitting device, comprising: utilizing a plurality of transmit chains of the electromagnetic transmitting device to transmit electromagnetic signals; adjusting at least one of a phase or an amplitude of at least one of the transmit chains based on a code, wherein: the codebook of code words is generated using at least one parameter that characterizes near-field electromagnetic radiation intensity of the electromagnetic signal transmitting device; the number of code words satisfies a criterion for quality of reception at an intended receiver; the code words are selected, during operation of the transmitting device, in response to data that are to be transmitted. ### Claim 2 (depends on 1) The method of claim 1, wherein the plurality of transmit chains are used to transmit a plurality of streams of data to the intended receiver. ### Claim 3 (depends on 1) The method of claim 1, wherein the electromagnetic radiation intensity includes specific absorption rate (SAR). ### Claim 4 (depends on 1) The method of claim 1, wherein the at least one parameter that characterizes the electromagnetic radiation intensity includes at least one predetermined phase angle between the transmit chains. ### Claim 5 (depends on 4) The method of claim 4, wherein the at least one predetermined phase angle is an angle corresponding to a predetermined electromagnetic radiation intensity. ### Claim 6 (depends on 1) The method of claim 1, wherein the near-field is within 10 transmission-frequency wavelengths of the device surface. ### Claim 7 (depends on 1) The method of claim 1, wherein the code maintains the electromagnetic radiation intensity below a threshold. ### Claim 8 (depends on 1) The method of claim 1, wherein the at least one parameter is stored in internal memory of the transmitting device. ### Claim 9 (depends on 1) The method of claim 1, wherein the at least one parameter is known to the intended receiver. ### Claim 10 (depends on 1) The method of claim 1, wherein the at least one parameter is determined offline during testing of the transmitting device, prior to usage of the transmitting device in operation. ### Claim 11 (depends on 1) The method of claim 1, wherein the criterion for quality of reception at an intended receiver is data rate. ### Claim 12 A method of transmission from an electromagnetic signal transmitting device, comprising: utilizing a plurality of transmit chains of the electromagnetic transmitting device to transmit electromagnetic signals; adjusting at least one of a phase or an amplitude of at least one of the transmit chains based on a code, wherein: the codebook of code words is generated using at least one parameter that characterizes the maximum permissible exposure (MPE) of the electromagnetic signal transmitting device; the number of code words satisfies a criterion for quality of reception at an intended receiver; the code words are selected, during operation of the transmitting device, in response to data that are to be transmitted. ### Claim 13 (depends on 12) The method of claim 12, wherein the plurality of transmit chains are used to beam form to the intended receiver. ### Claim 14 A transmitter, comprising: a plurality of transmit chains, wherein a transmission signal of at least one transmit chain includes at least one of an adjustable phase or an adjustable amplitude; a controller operative to adjust at least one of a phase or an amplitude of at least one of the transmit chains according to a code, wherein: the codebook of code words is generated using at least one parameter that characterizes electromagnetic radiation intensity of the electromagnetic signal transmitting device; the number of code words satisfies a criterion for quality of reception at an intended receiver; the code words are selected, during operation of the device, in response to data that are to be transmitted. ### Claim 15 (depends on 14) The transmitter of claim 14, wherein the plurality of transmit chains are used to beam form to the intended receiver. ### Claim 16 (depends on 14) The transmitter of claim 14, wherein the plurality of transmit chains are used to transmit a plurality of streams of data to the intended receiver. ### Claim 17 (depends on 14) The transmitter of claim 14, wherein the electromagnetic radiation intensity includes specific absorption rate (SAR). ### Claim 18 (depends on 14) The transmitter of claim 14, wherein the at least one parameter that characterizes the electromagnetic radiation intensity includes at least one predetermined phase angle between the transmit chains. ### Claim 19 (depends on 14) The transmitter of claim 14, wherein the electromagnetic radiation intensity includes maximum permissible exposure (MPE). ### Claim 20 (depends on 14) The transmitter of claim 14, wherein the code maintains the electromagnetic radiation intensity below a threshold. ### Claim 21 (depends on 14) The transmitter of claim 14, wherein the criterion of reception quality includes data rate to the intended receiver.