Radio frequency transmission

Abstract

An apparatus, comprising: means for decomposing an input signal into a plurality of substantially constant envelope components; a quadrature path for each of the substantially constant envelope components; means for performing discrete phase control in each of the quadrature paths; an amplifier in each of the quadrature paths; and means for combining the output signals from the quadrature paths.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to radio frequency transmission. Background Art

[0002] In order for radio signals to be transmitted over long distances, it is necessary to amplify them before transmission. Power amplifiers are commonly used for this purpose.

[0003] A power amplifier may be desired to linearly amplify a signal so that no non-linear distortion is generated in the amplified signal.

[0004] However, linear amplifiers are inefficient and may be expensive. Summary of the Invention

[0005] According to various but not necessarily all embodiments, there is provided an apparatus including:

[0006] means for decomposing an input signal into a plurality of substantially constant envelope components;

[0007] quadrature paths for each of the substantially constant envelope components;

[0008] means for performing discrete phase control in each of the quadrature paths;

[0009] an amplifier in each of the quadrature paths; and

[0010] means for combining the output signals from the quadrature paths.

[0011] In some but not necessarily all examples, the means for performing discrete phase control in each of the quadrature paths is configured to define constellation points in a constant envelope constellation for the quadrature path.

[0012] In some but not necessarily all examples, the apparatus includes means for providing discrete phase control in each of the quadrature paths to define constellation points in a constant envelope constellation for each of the quadrature paths, thereby defining target constellation points in a non-constant envelope constellation for the output signal.

[0013] In some but not necessarily all examples, each of the quadrature paths includes a phase controller that implements discrete phase control in the quadrature path, wherein the phase controller is configured to phase modulate a carrier.

[0014] In some but not all examples, the amplifier in each of the quadrature paths is a non-linear amplifier configured to amplify the substantially constant envelope component received by the quadrature path.

[0015] In some but not necessarily all examples, the apparatus includes means for providing the combined output signal of the quadrature paths to an antenna for transmission.

[0016] In some but not all examples, a system includes the apparatus for each of a plurality of antennas.

[0017] In some but not necessarily all examples, the system includes components for controlling discrete phase control in each quadrature path for each antenna to define constellation points in a constant envelope constellation for each quadrature path and thereby to define target constellation points in a non-constant envelope constellation for each output signal in the combined output signals provided to each of the antennas.

[0018] In some but not all examples, the components for decomposing an input signal into a plurality of substantially constant envelope components are configured to decompose the input signal into a plurality of substantially constant envelope components for all antennas.

[0019] In some but not necessarily all examples, the system includes components for optimizing a cost function across a plurality of antennas to determine the discrete phase control to be used for each quadrature path.

[0020] In some but not necessarily all examples, the cost function depends on the total transmission power of a plurality of antennas and a measurement of the difference between the information intended to be received and the information estimated to be received, the difference being a result of providing the combined output signals of the quadrature paths to the respective antennas for transmission.

[0021] In some but not necessarily all examples, the cost function depends on efficiency, such as the power efficiency of a transmitter, such as the power added efficiency of an amplifier used.

[0022] In some but not necessarily all examples, the cost function additionally depends on interference, such as out-of-band transmission.

[0023] In some but not necessarily all examples, a base station includes the system.

[0024] According to various but not necessarily all embodiments, a method is provided, including:

[0025] Decomposing an input signal into a plurality of substantially constant envelope components;

[0026] Providing discrete phase control and amplification for each substantially constant envelope component

[0027] After separate discrete phase control and amplification, combining the substantially constant envelope components.

[0028] According to various but not necessarily all embodiments, an apparatus is provided, including:

[0029] Decomposition components for decomposing an input signal into a plurality of substantially constant envelope components;

[0030] Quadrature paths for each substantially constant envelope component;

[0031] Components for discrete phase control in each quadrature path;

[0032] Amplifiers in each quadrature path; and

[0033] Combiners for each of a plurality of antennas, where each combiner combines different output signals from the quadrature paths to provide an antenna input signal for a corresponding antenna.

[0034] In some but not necessarily all examples, a decomposition component for decomposition is configured to provide joint spatial precoding and quadrature decomposition.

[0035] In some but not necessarily all examples, constellation points are defined for each antenna input signal for a corresponding antenna.

[0036] In some but not necessarily all examples, the components for providing discrete phase control in each quadrature path are configured to define constellation points in a constant envelope constellation for each quadrature path associated with an antenna, thereby defining target constellation points in the constant envelope constellation for the input signal of the antenna.

[0037] In some but not necessarily all examples, the transmitted signals from each antenna are combined over the air to generate symbols of the input signal at a receiver.

[0038] According to various but not necessarily all embodiments, examples are provided as claimed in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Some example embodiments will now be described with reference to the drawings, where:

[0040] Figure 1 Example embodiments of the subject matter described herein are shown;

[0041] Figure 2 Another example embodiment of the subject matter described herein is shown;

[0042] Figure 3 Another example embodiment of the subject matter described herein is shown;

[0043] Figure 4 Another example embodiment of the subject matter described herein is shown;

[0044] Figure 5 Another example embodiment of the subject matter described herein is shown;

[0045] Figure 6Shows another example embodiment of the subject matter described herein;

[0046] Figure 7 Shows another example embodiment of the subject matter described herein;

[0047] Figure 8 Shows another example embodiment of the subject matter described herein;

[0048] Figure 9 Shows another example embodiment of the subject matter described herein;

[0049] Figure 10 Shows another example embodiment of the subject matter described herein;

[0050] Figure 11 Shows another example embodiment of the subject matter described herein. Detailed Description

[0051] The following figures disclose various examples of apparatus 100, system 200, or base station 300, including:

[0052] A decomposition component 110 for decomposing an input signal 101 into a plurality of substantially constant envelope components S1, S2;

[0053] A quadrature path 120 for each substantially constant envelope component Sn n ;

[0054] A discrete phase control component 112 for performing discrete phase control in each quadrature path 120 n ; n ;

[0055] An amplifier 114 in each quadrature path 120 n ; and n ; and

[0056] A combining component 116 for combining the output signals from the quadrature paths 120 n ;

[0057] The term 'decompose' (and similar terms such as, for example, 'decomposition', 'decomposing', etc.) is used in its normal mathematical sense to mean separation into component parts. It is not intended to have or imply any particular technical meaning, or be limited to applications in a particular field or domain (such as digital / analog or linear / nonlinear).

[0058] The described decomposition is used for the heterophase and can thus be described as heterophase decomposition. In some examples described later, non-linear precoding provides joint (spatial) precoding and heterophase decomposition. Joint (spatial) precoding allows the use of discrete phase control (instead of continuous phase control) to control the transmission constellation points (instead of symbols) of each transmit antenna. Then, the signals from each antenna are combined over the air to generate symbols at the receiver. Thus, in at least some examples, the decomposition is achieved through joint (spatial) precoding and heterophase decomposition.

[0059] Figure 1 FIG. illustrates an example of apparatus 100, including:

[0060] A decomposition component 110 for decomposing an input signal 101 into a plurality of substantially constant envelope components S1, S2;

[0061] A heterophase path 120 for each substantially constant envelope component Sn n ;

[0062] A discrete phase control component 112 n , for performing discrete phase control in each heterophase path 120 n ;

[0063] An amplifier 114 in each heterophase path 120 n ; and n A combining component 116 for combining the output signals from the heterophase paths 120

[0064] n In the illustrated example, apparatus 100 includes:

[0065] A decomposition component 110 for decomposing the input signal 101 into two substantially constant envelope components S1, S2 for each transmit antenna;

[0066] A first heterophase path 1201 for the first substantially constant envelope component S1, including a first discrete phase control component 1121 for performing discrete phase control in the first heterophase path 1201 and a first amplifier 1141 in the first heterophase path 1201;

[0067] A second heterophase path 1202 for the second substantially constant envelope component S2, including a second discrete phase control component 1122 for performing discrete phase control in the second heterophase path 1202 and a second amplifier 1142 in the second heterophase path 1202;

[0068]

[0069] ​​Combined component 116, for combining the output signals from the first quadrature path 1201 and the output signals from the second quadrature path 1202.

[0070] In this example, the decomposition component 110 decomposes the input signal 101 into two substantially constant envelope components S1, S2 per transmit antenna. Each transmit antenna has two quadrature paths 1201, 1202, and their outputs are combined by the combining component 116. However, in other examples, the decomposition component 110 decomposes the input signal 101 into M (M≥2) substantially constant envelope components S1, S2...SM per transmit antenna, and each transmit antenna has M quadrature paths 1201, 1202...120 M , and their outputs are combined by the combining component 116 for transmission via the transmit antenna.

[0071] The circuit system 102 quadratures the transmission link circuit system. In this example, the quadrature transmission link circuit system 102 per transmit antenna includes a quadrature branch. In this example, the quadrature branch includes a plurality (two in this example) of quadrature paths 120 n and the combining component 116. Each quadrature path 120 n provides discrete phase control (discrete phase control component 112 n ) and amplitude control (amplifier 114 n ). In the illustrated example, the discrete phase control component 112 n and the amplifier 114 n are illustrated as being connected in series in a specific order. However, this order can be reversed.

[0072] Even if the amplifier 114 n in the quadrature path 120 n is non-linear, each quadrature path 120 n also provides linear amplification. Thus, the device 100 can achieve linear amplification using a cheaper and more energy-efficient non-linear amplifier instead of using a linear amplifier.

[0073] The amplifier 114 n in each quadrature path 120 n is configured for linearly amplifying the substantially constant envelope component Sn received by the quadrature path 120 n . In some examples, the amplifier 114 n is a non-linear power amplifier. In some examples, the same non-linear amplifier 114 n is used in each quadrature path 120 n . In some examples, the non-linear amplifier 114 n is class E or class F.

[0074] The device can be any suitable transmitter or transceiver. For example, it can be a network node, such as a base station, e.g., a cellular base station, e.g., Node B in 3GPP, or it can be a terminal, such as a cellular terminal, e.g., a mobile device (ME) or a user equipment (UE) in 3GPP.

[0075] As Figure 2 illustrated, the signal S to be amplified is decomposed into a plurality of substantially constant envelope signals S1, S2 such that their vector sum will substantially reconstruct the original signal S (S = S1 + S2). Since the decomposed signals S1, S2 are substantially constant envelope, even if the amplifier 114 n has non-linear characteristics over a large amplitude range, they can be amplified linearly by the amplifier 114 n with substantially constant envelope values. Thus, each amplifier 114 n can operate in an efficient non-linear mode. Then, for example, using a power combiner 116 n or an isolation combiner 116 n the outputs of the plurality of amplifiers 114 n are added together to produce an amplified version of the input signal as the output signal (e.g., G. S = G. S1 + G. S2, where G is the amplifier gain ).

[0076] The sum of the plurality of substantially constant envelope components S1, S2 supports substantially reconstructing the input signal 101 at the receiver when transmitted.

[0077] The plurality of amplifiers 114 n are constant envelope and thus consume a fixed amount of power.

[0078] By changing over time S the S1 phase (angle) between S and S2 and between

[0079] the substantially constant envelope component Sn can be adapted to the amplitude change of the signal S over time without changing the amplitude of S1 or S2. Thus S1 and S2 are constant envelope. n The substantially constant envelope component Sn can only fluctuate within a narrow operating efficiency range of the amplifier 114 n in the out-of-phase path 120 that receives the constant envelope component Sn.

[0080] The term "substantially" is used to indicate that in some examples, some small variations in magnitude can be accommodated. The term "fully" is used to indicate no variation in magnitude. The envelope can be substantially constant or fully constant. In cases where the term is not explicitly used, for example, in some patent offices where the term is not allowed in claims, it should be inferred.

[0081] Thus, the signal S(t) can be decomposed from the input sequence {S(t n )} into a sequence of multiple components, and each component sequence {S1(t n )}, {S2(t n )} has a constant magnitude over time, but the phase can vary discretely with the sequence.

[0082] The substantially constant envelope components S1, S2 can be provided as substantially constant envelope phasor components (digital domain) or substantially constant envelope analog signal components (analog domain). Each quadrature path 120 n includes components for:

[0083] Receiving one of the multiple substantially constant envelope components S1, S2 as a substantially constant envelope phasor component or a substantially constant envelope signal component;

[0084] Using a phase controller to modify one of the received multiple substantially constant envelope components S1, S2, and the phase controller implements discrete phase control in the quadrature path 120 n and the amplifier 114 in the quadrature path 120 n ; and n ; and

[0085] A combining component 116 for combining the modified multiple substantially constant envelope components S1, S2.

[0086] A discrete phase control component 112 for performing discrete phase control in each quadrature path 120 n is configured to define constellation points 132 in a constant envelope constellation 130 for the quadrature path 120 n . An example of a suitable constant envelope constellation 130 is illustrated in n . Figure 3 is illustrated.

[0087] Each quadrature path 120 n has an associated (constant magnitude) constellation 130. In some but not necessarily all examples, each quadrature path 120 n has the same associated (constant magnitude) constellation 130.

[0088] For combining from the quadrature path 120 nThe combining component 116 of the output signal is configured to provide, as output 111, a signal associated with the constellation point 142 in the non-constant envelope constellation 140. The combining component 116 can, for example, add the output signals from the quadrature path 120 n . In Figure 4 , an example of the non-constant envelope constellation 140 is illustrated. The non-constant envelope constellation 140 is a constellation formed by combining two signals having the same associated constant amplitude constellation 130 as illustrated Figure 3 .

[0089] The constant amplitude constellation 130 is characterized by a quantized phase and a fixed amplitude. The constellation points are located on a circle centered at the origin. In this example, the constellation points are evenly distributed on the circumference of the circle

[0090] The discrete phase control component 112 n is configured to add a quantum of phase 2π.m / N, where 0 ≤ m < N, and N is the number of constant amplitude constellation points 132, e.g., N can be equal to 2 in some examples n , where n is a natural number. In some examples, n is greater than or equal to 5. Adjacent constellation points 132 in the constant amplitude constellation 130 are separated by a low resolution or quantized phase of 2π / N

[0091] The non-constant envelope constellation 140 is characterized by a quantized phase and a quantized amplitude. The constellation points are located at the origin or on circles of different amplitude radii centered at the origin. In this example, the constellation points 142 distributed on the circumference of the circle are evenly distributed on the circumference of the circle

[0092] If the N constellation points 132 for S1 are defined by exp(2π.m1 / N) and the N constellation points 132 for S2 are defined by exp(2π.m2 / N), then the constellation points 142 for the combined signal are exp(2π.m1 / N) + exp(2π.m2 / N)

[0093] Compared with the constant amplitude constellation 130, the non-constant envelope constellation 140 has more constellation points 142 and a denser distribution of the constellation points 142

[0094] The discrete phase control component 112 n defines the constellation points 132 for its quadrature path 120 n in the constant amplitude constellation 130. In combination, they define the target constellation points 142 in the non-constant envelope constellation 140 for the output signal 111

[0095] In Figure 5 , each quadrature path 120 nIncluding a phase controller 112 controlled by decomposed signals S1 and S2 n , which is implemented to perform discrete phase control in the quadrature path 120 n . The decomposition component 110 is configured to control the discrete phase control in each phase controller 112 n .

[0096] In these examples, the phase controller 112 n is configured to perform phase modulation on the carrier wave.

[0097] The carrier wave is provided by a local oscillator (LO) 122 to each of the multiple phase controllers 112 n in the multiple phase controllers 112 n . The phase of the carrier wave is controlled by the phase controller 112 n via the decomposed signal Sn to have constellation points 132 in a constant envelope constellation. Therefore, each phase controller 112 n provides discrete (e.g., quantized) phase control for its quadrature path 120 n . After the discrete phase control, the signal is amplified by the corresponding amplifier 114 n of the quadrature path 120 n . The combining component 116 combines the amplified output signals from the quadrature paths 120 n to generate an amplified version of the carrier wave with target constellation points 142 in a non-constant envelope constellation 140 as the output. The combined output signal 111 of the quadrature paths 120 n is provided to the antenna 150 for transmission.

[0098] The circuit system 102 makes the transmission link circuit system in quadrature. In this example, the quadrature transmission link circuit system 102 includes one quadrature branch for each transmit antenna. In this example, each quadrature branch includes multiple (two in this example) quadrature paths 120 n , and includes a combining component 116.

[0099] In these examples, the signal 101 is provided via an evolved common public radio interface (eCPRI). This is an interface specification between the radio equipment control (REC) and the radio equipment (RE) of a radio base station for a cellular radio network. This interface can transmit baseband I / Q signals to the radio equipment. Other interfaces can be used.

[0100] In this example, the combining component 116 is an isolation combiner. Other combiners can be used.

[0101] In this example, the decomposition component 110 includes a circuit system for precoding. This circuit system decomposes the input signal 101 into signals for multiple corresponding quadrature paths 120n Multiple substantially constant envelope components Sn.

[0102] The circuitry for precoding can provide additional phase control. For example, controlling the signals provided to the quadrature paths 120 n such that when the signals from the quadrature paths 120 n are combined by the combining component 116, a target symbol, such as an OFDM symbol, is obtained for all quadrature paths of all antennas. When only using the low-resolution phase shifters 112 n OFDM symbols cannot be generated at each antenna 150. Instead, the signals from each antenna 150 are combined 'in the air' to generate OFDM symbols at the UE.

[0103] The (in-air) sum of all quadrature branches (not only those combined in a single Tx path) re-creates the desired signal (input signal 101) in a predetermined spatial direction (i.e., beam). This multi-antenna / in-air combination supports the use of effective / quantized quadrature paths and branches.

[0104] The quadrature transmission link circuitry 102 provides one quadrature branch for each transmit antenna 150, which branch includes multiple (two in this example) quadrature paths 120 n and a combining component 116.

[0105] In some examples, there are a number of quadrature branches, each quadrature branch including multiple quadrature paths 120 n , a non-linear power amplifier for each quadrature path, and a single combiner. The output of each quadrature branch is a constellation point 142 from the constellation 140. The input signal 101 is decomposed such that the sum of all quadrature paths (from all quadrature branches) reconstructs the desired signal (in a specific beam direction). In this example, there are at least two quadrature branches and at least two quadrature paths for each quadrature branch and at least four constant envelope signals S1, S2, S3, and S4, whose superposition (in the air) is similar to the input signal 101.

[0106] The decomposition component 110 serves the corresponding multiple antennas 150 via multiple quadrature branches.

[0107] In this example, the decomposition component 110 is circuitry for non-linear precoding and provides additional phase control. For example, as described above, controlling the signals provided to the quadrature paths 120 n to control beamforming of the multiple antennas 150. For example, controlling the signals provided to the quadrature paths 120 n such that when the signals from the quadrature paths 120 nWhen the signals of are combined in 116, the resulting signals from all the quadrature branches are combined in the air when transmitted through the antenna 150 to obtain the target symbol.

[0108] For example, a discrete phase control component 112 for the quadrature path 120 can be provided by a radio frequency phase shifter, a phase modulation phase-locked loop (PLL), a baseband phase shifter, or a Gaussian minimum shift keying (GMSK) chain. n of the quadrature path 120 n .

[0109] Figure 6 illustrates an example in which the discrete phase control component 112 for the quadrature path 120 n of the quadrature path 120 n is provided by a Gaussian minimum shift keying (GMSK) chain including a digital-to-analog converter 124 n , a Gaussian filter 126 n and a quadrature modulator 128. The quadrature modulator includes a local oscillator and a phase controller. A single local oscillator can be shared by multiple quadrature paths. The quadrature modulator provides a discrete phase control component for discrete phase control in each quadrature path 120 n . n for discrete phase control in each quadrature path 120.

[0110] Figure 7 illustrates a system 200, including: a decomposition component 110 for decomposing an input signal 101 into multiple substantially constant envelope components S1, S2 shared by multiple antennas 150.

[0111] Generate S1, S2 signals for each antenna. Thus, they are different for individual antennas.

[0112] The system 200 includes a quadrature branch of the quadrature transmit link circuitry 102 for each antenna among the multiple antennas, and each quadrature path 120 n (as previously described) for each substantially constant envelope component Sn. Each quadrature path 120 n has a discrete phase control component 112 for discrete phase control in each quadrature path 120 n and an amplifier 114 in each quadrature path 120 n and a combining component 116 for combining the output signals from the quadrature paths 120. The combined output signal of the quadrature path 120 n is provided to the corresponding antenna 150 for transmission. n The combined output signal of the quadrature path 120 n is provided to the corresponding antenna 150 for transmission. n The combined output signal of the quadrature path 120 is provided to the corresponding antenna 150 for transmission.

[0113] Each quadrature path 120 in the system 200 n amplifies the constant envelope component. In some examples, each quadrature path 120n The magnitudes of the constant envelope components in n can be the same, such that all the out-of-phase paths 120

[0114] The decomposition component 110 controls each out-of-phase path 120 n for each antenna 150 with discrete phase control, so that for each out-of-phase path 120 n a constellation point 132 in the constant envelope constellation 130 is defined, thereby defining a target constellation point in the non-constant envelope constellation 140 for each output signal in the combined output signal provided to each antenna 150 among the antennas 150.

[0115] The decomposition component 110 is configured to jointly decompose the input signal 101 into a plurality of basic constant envelope components Sn for all the antennas 150.

[0116] Figure 8 An example of a system 200 for beamforming is illustrated. For example, it can be configured for massive multiple-input multiple-output (mMIMO).

[0117] For example, each antenna 150 is arranged in a regular array. As Figure 7 illustrated, the signal for each antenna is provided by the corresponding out-of-phase branch of the out-of-phase transmission chain circuit system 102.

[0118] The array can include, for example, 64*X antennas, where X = 2^n and n = 0, 1, 2, 3.... For example, in some examples, there can be 64, 128, 256, 512... antennas 150 in the array.

[0119] Figure 9 An example of a base station 300 including the system 200 as previously described is illustrated. The base station can be constructed more inexpensively and can be operated more inexpensively because less expensive and / or more power-efficient amplifiers 114 can be used.

[0120] In the foregoing example, the decomposition component 110 (or some other processing component or circuit system) can be configured to optimize a cost function across multiple antennas 150 to determine the discrete phase control for each out-of-phase path 120 n of.

[0121] An example of the cost function is:

[0122]

[0123] Subject to

[0124] [A] (m，n) ∈χ

[0125]

[0126] where f n is the (m,n)-th element of the NxN DFT matrix, which is equal to the n-th column of the DFT matrix

[0127] I (eff(A)≥η) is an indicator function defined, for example, as follows

[0128]

[0129] is the time-domain signal on all antennas,

[0130] H[n] is the channel matrix at subcarrier n

[0131] M and N correspond to the number of antennas and the FFT size,

[0132] N u is the index of the used subcarriers,

[0133] χ is the constellation generated by the low-resolution phase shifters

[0134] This constraint constrains the efficiency of the out-of-phase architecture, thus achieving an efficiency of at least η.

[0135] In this example, the cost function depends on the total transmit power of multiple antennas. In the above example cost function, the dependence on the total transmit power is provided by provided.

[0136] In this example, the cost function depends on the measurement of the difference between the information intended to be received and the information estimated to be received, and thus the corresponding combined output signal of the out-of-phase path 120n is provided to the corresponding antenna for transmission.

[0137] The measure of the difference can be, for example, the signal-to-noise and distortion ratio (SNDR) or the error vector magnitude (EVM) that quantifies the precision of the generated signal. The SNDR is the ratio of the total signal power level (signal + noise + distortion) to the power of the unwanted signal (noise + distortion).

[0138] In the above example cost function, the measure of the difference is provided by the squared difference between the information u[n] intended to be received and the information αH[n]x[n] estimated to be received, summed over all antennas:

[0139]

[0140] In this example cost function, there is a constellation constraint because the phase control can be quantified in a predetermined manner. In the above example cost function, the optimization of the cost function is constrained

[0141] [A] (m，n) ∈χ

[0142] In some examples, the cost function can depend on efficiency. For example, it may be required that the efficiency be higher than a threshold.

[0143] In the above example cost function, the dependence on efficiency is provided by I {eff(A)≥η} provided.

[0144] In some examples, the cost function can additionally depend on interference, such as out-of-band transmission. For example, it may be required that the out-of-band transmission be lower than a threshold. This can be particularly useful when using orthogonal frequency division multiplexing (OFDM).

[0145] In the above example cost function, the dependence on out-of-band transmission is provided by provided.

[0146] The optimization of the cost function can be solved using a greedy optimization algorithm. The greedy optimization algorithm treats each component of the cost function as independent and iteratively finds the optimized value of each component of the cost function.

[0147] This optimization finds the best A, where each element of A belongs to one of the constellation points 140 in the constellation χ. For example, A = S1 + S2, where S1 and S2 are Figure 3 constellation points 132 in, and A is Figure 4 constellation point 142 in.

[0148] In Figure 10 the results of using an appropriately specified cost function can be seen, which balances reducing the transmission power while maintaining the efficiency. Figure 10 is a histogram of the signal constellation points 42 at any antenna 150. When compared with the internal constellation points, the external larger magnitude constellation points 142 from the out-of-phase are more often selected. The external constellation points have a higher output power and thus higher efficiency compared to the internal constellation points.

[0149] Multiple amplifiers 114 n are constant envelope and thus consume a fixed amount of power. Reducing the output power while maintaining a fixed power consumption reduces the efficiency

[0150] Figure 11 Illustrates an example of the previously described method 400. The method includes:

[0151] At block 402, decomposing the input signal 101 into a plurality of substantially constant envelope components {Sn};

[0152] At block 404, discrete phase control and amplification are provided for each substantially constant envelope component Sn; and

[0153] At block 406, the substantially constant envelope components {Sn} are combined after individual discrete phase control and amplification.

[0154] The individual discrete phase control 404A and amplification 404B of each component in the constant envelope component {Sn} can occur simultaneously and in parallel.

[0155] As used in this application, the term 'circuitry' can refer to one or more or all of the following:

[0156] (a) Only hardware circuitry implementations (such as those in only analog and / or digital circuitry); and

[0157] (b) Combinations of hardware circuitry and software, such as (if applicable):

[0158] (i) Combinations of (multiple) analog and / or digital hardware circuitry with software / firmware, and

[0159] (ii) Any portions of (multiple) hardware processors with software (including (multiple) digital signal processors), software, and (multiple) memories that work together to enable a device such as a mobile phone or server to perform various functions, and

[0160] (c) (Multiple) hardware circuitry and / or (multiple) processors that require software (such as firmware) to operate, such as (multiple) microprocessors or portions of (multiple) microprocessors, but the software may not be present when not needed for operation.

[0161] This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry will also cover implementations of only hardware circuitry or processors and their accompanying software and / or firmware. For example and if applicable to a particular claim element, the term circuitry will also cover baseband integrated circuits for mobile devices or similar integrated circuits in a server, cellular network device, or other computing or networking device.

[0162] Figure 11 The illustrated blocks may represent steps in a method and / or code segments in a computer program. The illustration of a particular order of the blocks does not necessarily mean that the blocks have a required or preferred order, and the order and arrangement of the blocks may be changed. Additionally, it is possible that some blocks may be omitted.

[0163] The foregoing device 100, system 200, and base station 300 include:

[0164] A decomposition component 110 for decomposing an input signal 101 into a plurality of substantially constant envelope components S1, S2;

[0165] A plurality of quadrature paths 120n, where each quadrature path 120n includes components for:

[0166] Receiving one of the plurality of substantially constant envelope components S1, S2;

[0167] Modifying one of the received plurality of substantially constant envelope components S1, S2 using a phase controller that implements discrete phase control in the quadrature path 120n;

[0168] An amplifier 114n in the quadrature path 120n; and

[0169] A combining component 116 for combining the modified plurality of substantially constant envelope components S1, S2.

[0170] In cases where structural features have been described, a structural feature may be replaced by a component for performing one or more functions of the structural feature, whether those functions are explicitly or implicitly described.

[0171] The term 'comprising' is used herein in an inclusive rather than an exclusive sense. That is, any reference to X that comprises Y indicates that X may include only one Y or may include more than one Y. If an exclusive sense of 'comprising' is intended, it will be made apparent in the context by reference to "including only one..." or by using "consisting of".

[0172] In this description, various examples have been referred to. A description of a feature or function of an example indicates that those features or functions exist in that example. Whether explicitly stated or not, the terms 'example' or 'for example' or 'can' or 'may' are used herein to indicate that such a feature or function exists at least in the described example, whether described as an example or not, and they may but need not exist in some or all other examples. Thus, 'example', 'for example', 'can', or'may' refer to a particular instance within a class of examples. The attributes of an instance may be attributes of only that instance or attributes of such a class or a subclass of such a class that includes some but not all instances of the class. Thus, features described with reference to one example rather than another are implicitly disclosed as being usable, where possible, as part of a working combination in that other example without necessarily being used in that other example.

[0173] Although the embodiments have been described with reference to various examples in the foregoing paragraphs, it should be understood that the examples given can be modified without departing from the scope of the claims.

[0174] In addition to the combinations explicitly described above, the features described in the foregoing description can be used in combination.

[0175] Although functions have been described with reference to certain features, those functions can be performed by other features, whether or not described.

[0176] Although features have been described with reference to certain embodiments, those features can also be present in other embodiments, whether or not described.

[0177] The terms 'a' or 'the' are used herein in an inclusive rather than an exclusive sense. That is, any reference to X that includes a / the Y indicates that X can include only one Y or can include more than one Y, unless the context clearly indicates the contrary. If an exclusive sense of 'a' or 'the' is intended, it will be apparent from the context. In some cases, the use of 'at least one' or 'one or more' can be used to emphasize the inclusive sense, but the absence of these terms should not be taken as inferring an exclusive sense.

[0178] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and to features (equivalent features) that achieve substantially the same technical effect. Equivalent features include, for example, features that are variants and that achieve substantially the same result in substantially the same way. Equivalent features include, for example, features that perform substantially the same function in substantially the same way to achieve substantially the same result.

[0179] In this description, various examples using adjectives or adjective phrases have been referred to in order to describe the characteristics of the examples. Such a description of the characteristics with respect to an example indicates that the characteristic is exactly the same as described in some examples and substantially the same as described in other examples.

[0180] Although attempts have been made in the foregoing specification to draw attention to those features that are considered particularly important, it should be understood that the applicant can seek protection via the claims for any patentable feature or combination of features cited above and / or shown in the drawings, whether or not such point has been emphasized.

Claims

1. A system for communication, comprising: means for decomposing an input signal into a plurality of constant envelope components for each of a plurality of antennas; a device, the device comprising: a quadrature path for each constant envelope component; means for discrete phase control in each quadrature path; an amplifier in each quadrature path; means for combining output signals from the quadrature paths; and means for providing the combined output signal of the quadrature paths of the device to a corresponding one of the plurality of antennas for transmission; and means for optimizing a cost function across the plurality of antennas to determine the discrete phase control to be used for each quadrature path, wherein the optimization seeks an optimal A, where A is a time-domain signal across all antennas, and wherein the specified cost function is arranged to balance reducing the transmission power value while maintaining efficiency.

2. The system according to claim 1, wherein the means for discrete phase control in each quadrature path is configured to: define constellation points in a constant envelope constellation for the quadrature path.

3. The system according to claim 2, wherein the device comprises means for: providing discrete phase control in each quadrature path to define constellation points in the constant envelope constellation for each quadrature path, and thereby define target constellation points in a non-constant envelope constellation for the output signal.

4. The system according to claim 1, wherein each quadrature path includes a phase controller that implements discrete phase control in the quadrature path, wherein the phase controller is configured to phase modulate a carrier.

5. The system according to claim 1, wherein the amplifier in each quadrature path is a non-linear amplifier configured to amplify the constant envelope component received by the quadrature path.

6. The system according to claim 1, comprising means for: controlling the discrete phase control in each quadrature path for each antenna to define constellation points in a constant envelope constellation for each quadrature path, and thereby define target constellation points in a non-constant envelope constellation for each output signal of the combined output signals provided to each of the antennas through the air.

7. The system according to claim 1, wherein the means for decomposing the input signal into a plurality of constant envelope components is configured to: decompose the input signal into a plurality of constant envelope components for all antennas.

8. The system according to claim 1, wherein the cost function depends on the total transmission power of the plurality of antennas and a measurement of the difference between the information intended to be received and the information estimated to be received, the difference being a result of providing the corresponding combined output signal of the quadrature paths to the corresponding antenna for transmission.

9. The system according to claim 1, wherein the cost function depends on efficiency.

10. The system according to claim 1, wherein the cost function additionally depends on interference.

11. A base station comprising the system according to any one of claims 1 to 10.

12. A communication method, comprising: Decomposing an input signal into a plurality of constant envelope components for each of a plurality of antennas; Providing discrete phase control and amplification for each of the constant envelope components; Combining the constant envelope components after separate discrete phase control and amplification; Providing the combined constant envelope components to a corresponding one of the plurality of antennas for transmission; And Optimizing a cost function across the plurality of antennas to determine discrete phase control to be used for each out-of-phase path, wherein the optimization seeks an optimal A, where A is a time-domain signal across all antennas, and wherein the specified cost function is arranged to balance reducing a transmission power value while maintaining efficiency.

Images