1. In a wireless transmission system adapted for use with a portable mobile device, a method for processing signals in preparation for wireless transmission, wherein the wireless transmission includes use of a power amplifier, the method comprising:
maintaining a lookup table that contains pre-computed distortion contributions determined by monitoring the power amplifier following initialization of the power amplifier and prior to transmission, wherein determining distortion contributions includes:
squaring an in-phase component of a signal representative of power amplifier output to produce a squared in-phase output value:
squaring a quadrature component of the signal representative of power amplifier output to produce a squared quadrature output value;
squaring an in-phase component of a signal representative of an input signal to produce a squared in-phase input value;
squaring a quadrature component of the signal representative of the input signal to produce a squared quadrature input value;
determining an in-phase difference between the squared in-phase input value and the squared in-phase output value; and
determining a quadrature difference between the squared quadrature input value and the squared quadrature output value, the distortion contributions being based on the in-phase difference and the quadrature difference;
accepting a value that reflects information to be communicated, the value hereinafter referred to as original value;
generating a lookup-table key based on the original value, wherein the lookup-table key is digital;
retrieving from the lookup table, using the lookup-table key, a pre-computed distortion contribution for the original value;
distorting the original value based on the pre-computed distortion contribution to obtain a distorted value to pre-compensate for nonlinear characteristics of the power amplifier; and
wirelessly transmitting based on the distorted value.
2. The method according to claim 1, further comprising:
establishing the pre-computed distortion contributions by training based on errors observed from feedback based on output of the power amplifier.
3. The method according to claim 2, wherein both the reference information and the pre-computed distortion contributions are established within four seconds.
4. The method according to claim 2, further comprising refraining, once the pre-computed distortion contributions are computed, for at least one entire telephone conversation, from further training to compute the pre-computed distortion contributions or the reference information.
5. The method according to claim 2, wherein the feedback is hereinafter referred to as pre-compensation training feedback, the establishing step comprising:
storing information, hereinafter referred to as reference information, that models characteristics, hereinafter referred to as reference characteristics, that are more linear than the nonlinear characteristics; and
establishing the reference information by training based on errors observed from feedback, hereinafter referred to as reference training feedback, based on output of the power amplifier;
wherein the errors observed from the pre-compensation training feedback comprise an error between the pre-compensation training feedback and the reference information.
6. The method according to claim 5, wherein the power amplifier operates in a first range during operational wireless transmission; and the step of establishing the reference information further comprises setting the power amplifier to operate in a second range for training to establish the reference information, wherein the power amplifier has more linear characteristics when operating in the second range as compared to when operating in the first range.
7. In a wireless transmission system adapted for use with one or more portable mobile devices, a method for processing signals in preparation for wireless transmission, wherein the wireless transmission includes use of a power amplifier for transmitting a plurality of channels, the method comprising:
operating the transmission system in a training mode,
monitoring the operating characteristics of a power amplifier while operating in the training mode,
computing values representative of nonlinearity in the power amplifier at a plurality of operating conditions and storing the computed nonlinearity values while operating in the training mode, the computing step comprising at least in part:
squaring an in-phase component of a signal representative of power amplifier output to produce a squared in-phase output value;
squaring a quadrature component of the signal representative of power amplifier output to produce a squared quadrature output value;
squaring an in-phase component of a signal representative of an input signal to produce a squared in-phase input value;
squaring a quadrature component of the signal representative of the input signal to produce a squared quadrature input value,
determining an in-phase difference between the squared in-phase input value and the squared in-phase output value; and
determining a quadrature difference between the squared quadrature input value and the squared quadrature output value, the distortion contributions being based on the in-phase difference and the quadrature difference;
computing values of channel delay at a plurality of operating conditions and storing the computed channel delay values while operating in the training mode, and
operating the transmission system in a normal operating mode and using the nonlinearity and channel delay values stored while in training mode to predistort input to the power amplifier so as to linearize the output of the power amplifier.
8. The signal processing method of claim 7 further comprising the step of switching from normal operating mode to training mode and repeating the monitoring, computing and storing steps, and then switching back to normal operating mode.
9. The signal processing method of claim 7 wherein the predistortion of the input to the power amplifier is performed in real time.
10. The signal processing method of claim 7 wherein the signal processing is performed feedforward.
11. The signal processing method of claim 7 wherein the stored signals are obtained through adaptive iteration.
12. The signal processing method of claim 7 wherein the training mode is used only at initialization of the power amplifier.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for removing sulfur compounds contained in a hydrocarbon-containing gas comprising feeding a hydrocarbon-containing gas to a desulfurizing bed to remove sulfur compounds contained in the hydrocarbon-containing gas, wherein the desulfurizing bed comprises:
a desulfurizing agent A comprising at least one metal component selected from the group consisting of Ag, Cu, Ni, Zn, Mn, Fe, Co, an alkali metal, an alkaline earth metal and a rare earth metal carried on a zeolite; and
a desulfurizing agent B comprising at least one selected from the group consisting of cerium oxide and a metal component-carried on a porous inorganic oxide,
wherein
the metal component-carried on a porous inorganic oxide is one selected from the group consisting of Ag, Cu, Ni, Zn, Mn, Fe, Co, Al, Si, an alkali metal, an alkaline earth metal and a rare earth metal, and
the porous inorganic oxide is at least one selected from the group consisting of alumina, silica, silica-alumina and cerium oxide.
2. The method for removing sulfur compounds contained in a hydrocarbon-containing gas as described in claim 1, wherein
the desulfurizing agent A has a higher desulfurizing performance to sulfides and disulfides than that of the desulfurizing agent B, and
the desulfurizing agent B has a higher desulfurizing performance to carbonyl sulfide than that of the desulfurizing agent A.
3. The method for removing sulfur compounds contained in a hydrocarbon-containing gas as described in claim 1, wherein a volume ratio of the desulfurizing agent A to the desulfurizing agent B in the desulfurizing bed is 0.1:0.9 to 0.9:0.1.
4. The method for removing sulfur compounds contained in a hydrocarbon-containing gas as described claim 1, wherein zeolite in the desulfurizing agent A has a beta (BEA) andor faujasite (FAU) structure.
5. The method for removing sulfur compounds contained in a hydrocarbon-containing gas as described claim 1, wherein a temperature of the desulfurizing bed is \u221220 to 100\xb0 C.
6. A hydrocarbon-containing gas for a fuel cell obtained according to the method of claim 1, wherein a concentration of carbonyl sulfide is 0.1 weight ppm or less.
7. The hydrocarbon-containing gas for a fuel cell as described in claim 6, wherein the hydrocarbon-containing gas for a fuel cell is at least one selected from natural gas, city gas, LPG, a naphtha fraction and dimethyl ether.
8. A method for removing sulfur compounds contained in a hydrocarbon-containing gas, wherein a desulfurizing agent comprising at least zeolite is used to remove sulfur compounds contained in the raw material hydrocarbon-containing gas for a fuel cell as described in claim 6.
9. A method to produce hydrogen for a fuel cell, comprising:
removing sulfur compounds contained in a hydrocarbon-containing gas by the method as described in claim 1, and
then contacting the hydrocarbon-containing gas from which the sulfur compounds have been removed with one selected from the group consisting of a partial oxidation reforming catalyst, an autothermal reforming catalyst and a steam reforming catalyst.
10. The method for producing hydrogen for a fuel cell as described in claim 9, wherein the partial oxidation reforming catalyst, the autothermal reforming catalyst or the steam reforming catalyst is a ruthenium base or nickel base catalyst.
11. A method for producing hydrogen for a fuel cell, wherein the hydrocarbon-containing gas as described in claim 6 is a raw material.
12. A method for producing hydrogen for a fuel cell, comprising:
removing the sulfur compounds contained in the hydrocarbon-containing gas as described in claim 6, and then
contacting the hydrocarbon-containing gas from which the sulfur compounds have been removed with one selected from the group consisting of a partial oxidation reforming catalyst, an autothermal reforming catalyst and a steam reforming catalyst.
13. The method for producing hydrogen for a fuel cell as described in claim 12, wherein the partial oxidation reforming catalyst, the autothermal reforming catalyst or the steam reforming catalyst is a ruthenium base or nickel base catalyst.
14. The method for removing sulfur compounds contained in a hydrocarbon-containing gas as described in claim 1, wherein
the desulfurizing agent A comprises zeolite having a beta (BEA) andor faujasite (FAU) structure and at least one metal component selected from the group consisting of Ag and Cu, and
the desulfurizing agent B comprises at least one selected from the group consisting of cerium oxide and a metal component-carried on a porous inorganic oxide, wherein
the metal component is at least one selected from the group consisting of Ag, Cu and Ni, and
the porous inorganic oxide is at least one selected from the group consisting of alumina, silica-alumina and cerium oxide.