Multiple antenna transmission to manage radiated power
Increased radiated power using multiple antennas is disclosed. In certain aspects, power spectral density limitations on a per antenna basis can be met while increasing radiated power for a shared channel by transmitting the signal over multiple antennas. Further aspects relate to allocating a monolithic block of modulation as a single cluster to minimize the required power back-off and maximize power density.
1 . A mobile device comprising:
at least two antennas; and
a radio frequency front-end including at least two transmit chains, each of the transmit chains including a power amplifier configured to amplify a radio frequency signal and transmit the amplified radio frequency signal via a corresponding one of the at least two antennas, the amplified radio frequency signal has a power less than a threshold power level at each of the antennas, the radio frequency front-end configured to share a channel of an unlicensed band with one or more other radio frequency devices, the channel being split into a plurality of monolithic blocks corresponding to the front-end and the one or more other radio frequency devices such that each of the front-end and the one or more other radio frequency devices is configured to use the corresponding monolithic block of the channel of the unlicensed band.
2 . The mobile device of claim 1 wherein at least one of the transmit chains is a WiFi transmit chain.
3 . The mobile device of claim 1 wherein a combined uplink power of the at least two transmit chains is greater than the threshold power level.
4 . The mobile device of claim 1 wherein the at least two transmit chains are further configured to transmit the amplified radio frequency signal with less power back-off compared to a single transmit chain transmitting the radio frequency signal with a power less than the threshold power level.
5 . The mobile device of claim 1 wherein the at least two transmit chains include at least four transmit chains each configured to transmit the amplified radio frequency signal, and a combined uplink power of the at least four transmit chains is about 6 dB greater than the threshold power level.
6 . The mobile device of claim 5 wherein the at least two antennas include four antennas, and each of the four transmit chains are configured to transmit the amplified radio frequency signal via a corresponding one of the four antennas.
7 . A method of using a radio frequency device comprising:
receiving a radio frequency signal at a radio frequency front end including at least two transmit chains of a radio frequency device, each of the transmit chains including a power amplifier;
independently amplifying the radio frequency signals using each of the power amplifiers;
transmitting the amplified radio frequency signals via at least two antennas respectively coupled to the at least two transmit chains, each of the transmitted amplified radio frequency signals having a power less than a threshold power level at each of the antennas; and
sharing, using the radio frequency front end, a channel of an unlicensed band with one or more other radio frequency devices, the channel being split into a plurality of monolithic blocks corresponding to the radio frequency front end and the one or more other radio frequency devices such that each of the radio frequency front end and the one or more other radio frequency devices is configured to use the corresponding monolithic block of the channel of the unlicensed band.
8 . The method of claim 7 wherein at least one of the transmit chains is a WiFi transmit chain.
9 . The method of claim 7 further comprising transmitting the radio frequency signal via the at least two transmit chains with less power back-off compared to a single transmit chain transmitting the amplified radio frequency signal with a power less than the threshold power level.
10 . The method of claim 7 wherein a combined uplink power of the at least two transmit chains is greater than the threshold power level.
11 . The method of claim 7 herein the at least two transmit chains include four transmit chains configured to transmit the radio frequency signal, and a combined uplink power of the four transmit chains is about 6 dB greater than the threshold power level.
12 . A radio frequency device comprising:
front-end circuitry including at least two transmit chains, each of the transmit chains configured to transmit an amplified radio frequency signal via a corresponding one of at least two antennas, the amplified radio frequency signal having a power less than a threshold power level at each of the transmit chains, the front-end circuitry configured to share a channel of a frequency band with one or more other radio frequency devices, the channel being split into a plurality of monolithic blocks corresponding to the front-end circuitry and the one or more other radio frequency devices such that each of the front-end circuitry and the one or more other radio frequency devices is configured to use the monolithic block of the channel of the frequency band.
13 . The device of claim 12 wherein each of the transmit chains includes a power amplifier configured to generate the amplified radio frequency signal.
14 . The device of claim 12 wherein at least one of the transmit chains is a WiFi transmit chain.
15 . The device of claim 12 wherein a combined uplink power of the at least two transmit chains is greater than the threshold power level.
16 . The device of claim 12 wherein the at least two transmit chains are further configured to transmit the amplified radio frequency signal with less power back-off compared to a single transmit chain transmitting the radio frequency signal with a power less than the threshold power level.
17 . The device of claim 12 wherein the at least two transmit chains include at least four transmit chains each configured to transmit the amplified radio frequency signal, a combined uplink power of the four transmit chains is about 6 dB greater than the threshold power level.
18 . The device of claim 17 wherein each of the four transmit chains are configured to transmit the amplified radio frequency signal via a corresponding one of at least four antennas.
19 . The device of claim 12 wherein the frequency band is an unlicensed band.
20 . A front-end module including the radio frequency device of claim 12 .