TWI556613B - Blind technique for weight selection in simultaneous transmit and receive structure - Google Patents

Description

Blind technology for weight selection in synchronous transmit and receive structures Field of invention

Embodiments relate to wireless communication. Some embodiments relate to transmitting signals in a wireless network including their networks operating on the 3GPP Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Advanced Networking (LTE-A) Advanced Network Standard.

Background of the invention

In many wireless communication systems, weights are often used to control the value of the echo cancellation signal produced by the echo canceller of the system. The echo canceller can use the echo cancellation signal to eliminate echo signals that are not readily seen in the receiving path of the system. The echo signal may be the portion of the signal from the transmission path of the system that leaks into the receive path. The value of the weight is often chosen such that the value of the echo cancellation signal is as close as possible to the value of the echo signal in order to have an efficient echo cancellation operation. In some conventional systems, techniques for selecting such values of weights may result in complex echo cancellation structures, slow cancellation operations, or both.

According to an embodiment of the present invention, an echo canceler for use in a wireless communication system is provided, the echo canceler comprising: a phase shifter for generating an output signal, wherein the phase shifters are Each generating one of the output signals, each of the output signals having a phase shift relative to one of the transmitted signals; an attenuator unit for attenuating the phase shifters based on the weights The output signal of each of the output signals to generate an attenuated signal, each of the attenuated signals corresponding to the output signal of one of the phase shifters; a weight calculator for Performing an operation for selecting the equivalent of the weights without using a component associated with the transmitted signal as an input for calculating the value of the weights; and at least one summer, The received signal is summed with the received signal containing one of the echo signals to produce an echo canceled signal.

100‧‧‧Wireless communication system

101, 401‧‧‧ Echo canceller

102, 402, 404‧‧‧ antenna

103‧‧‧Delay

110, 410‧‧‧ Receiver

111‧‧‧Low noise amplifier

112, 163‧‧ ‧ down converter

113, 164‧‧‧ analog to digital converter

120, 420‧‧ ‧ transmitter

121‧‧‧Digital to analog converter

122‧‧‧Upconverter

123‧‧‧Power Amplifier

131, 132‧‧‧ vector modulator

141, 142, 143‧‧‧ stationary phase shifter

151, 152, 153‧‧‧ attenuators

154, 155‧‧‧sumer

160‧‧‧weight calculator

161‧‧‧Bandpass filter

162‧‧•Variable Gain Amplifier

165‧‧‧Periodic measurement unit

Unit 166‧‧‧

167‧‧‧ weight selection unit

170‧‧‧Power monitor

200‧‧‧ method

201~299‧‧‧ activities

300‧‧‧Wireless communication network

302‧‧‧Website

311, 312, 400‧‧‧ wireless communication devices

313, 315‧‧‧ Wireless connection

405‧‧‧ transceiver

415‧‧‧ Controller

430‧‧‧ memory

1 is a block diagram of a wireless communication system including an echo canceler in accordance with some embodiments described herein.

2 is a flow chart showing a method for operating a wireless communication system, including methods for selecting weights to control the attenuator of the echo canceler, in accordance with some embodiments described herein.

3 shows a wireless communication network including a network station and a wireless communication device in accordance with some embodiments described herein.

4 shows a block diagram of a wireless communication device including an echo canceler in accordance with some embodiments described herein.

Detailed description of the preferred embodiment

The following description and the drawings are intended to be illustrative of specific embodiments Other embodiments may incorporate structural changes, logic changes, electrical changes, process changes, and other changes. Portions and features of some embodiments may be included or substituted for those of other embodiments. The embodiments set forth in the claims below cover all available equivalents of the claims.

1 is a block diagram of a wireless communication system 100 including an echo canceler 101 in accordance with some embodiments described herein. The wireless communication system 100 can have both transmit (Tx) and receive (Rx) (STR) capabilities (e.g., full duplex capability) such that it can simultaneously transmit and receive signals. As shown in FIG. 1, wireless communication system 100 can include an antenna 102, a receiver 110, and a transmitter 120 for receiving an incoming signal r(t). Receiver 110 can include a low noise amplifier (LNA) 111, a down converter 112, and an analog to digital converter (ADC) 113, each configured to process signals from antenna 102. Transmitter 120 can include a digital to analog converter (DAC) 121, an upconverter 122, and a power amplifier (PA) 123, each configured to generate an analog signal x(t) based on the digital signal x(n) for It is transmitted from the wireless communication system 100 to other devices.

The transmission of signal x(t) (transmitted signal) from transmitter 120 may form an echo (e.g., an echo signal) in the receive chain of wireless communication system 100. The echo may be contained in the signal y(t), which is also referred to as the received signal containing the echo. Thus, y(t) may include a combination of desired signals plus echoes transmitted from another device or system to the wireless communication system 100.

To cancel (eg, reduce or remove) the echo, the echo canceler 101 is configured to perform an echo cancellation operation to estimate the echo, generate an echo cancellation signal, and then receive the received signal from the echo y(t) The echo cancellation signal is subtracted to produce an echo cancelled signal z(t). In FIG. 1, the echo cancellation signal may include a combination (eg, sum) of signals x ₁ (t) and x ₂ (t), which is the output signal at the output of the echo canceler 101. The echo canceler 101 can subtract the signals x ₁ (t) and x ₂ (t) from the received signal containing the echo y(t) to produce an echo canceled signal z(t).

Signal x ₁ (t) and signal x ₂ (t) may be generated based on signals from selected taps on the signal path of transmitted signal x(t). 1 shows an example configuration in which two taps (eg, two tap filters with taps T=2) may be selected for use in echo canceller 101 to generate two corresponding signals x ₁ (t) and signal x. ₂ (t) The transmitted signal x(t). The two taps of the examples are associated with two delays τ ₁ and τ ₂ . Other configurations are available. For example, more than two taps (eg, T > 2) may be used to generate an echo cancellation signal (combination of signals x ₁ (t) and x ₂ (t)) at the output of the echo canceler 101.

As shown in FIG. 1, echo canceller 101 can include a vector modulator 131 for generating a signal x ₁ (t) based on a selected tap (eg, a tap associated with T = 1 of the filter) and A vector modulator 132 that produces a signal x ₂ (t) is based on another selected tap (eg, a tap associated with T=2 of the filter). Figure 1 shows, as an example, two vector modulators 131 and 132 for generating two corresponding signals (e.g., x ₁ (t) and x ₂ (t)), the number of vector modulators being variable.

The value of signal x ₁ (t) and signal x ₂ (t) can be controlled by the value of the weight used in the corresponding vector modulator. For example, as shown in FIG. ₁ , weights w ₁ , w _{2 ,} and w ₃ can be used in vector modulator 131 to control the value of signal x ₁ (t). The weights w ₄ , w ₅ and w ₆ can be used in the vector modulator 132 to control the value of the signal x ₂ (t). By appropriately selecting the values of such weights (e.g., w ₁ to w _k , where k = 6 in this example), the signals x ₁ (t) and x ₂ (to cancel the echo) can be appropriately obtained ( t) The value.

The echo canceller 101 can include a weight calculator 160 configured to calculate and select values for the weights w ₁ through w _k . The weight calculator 160 can use the signal Z(n) for calculating the values of the weights w ₁ to w _k . The signal Z(n) is a digital baseband signal generated based on the echo cancelled signal z(t). As described in more detail below, the weight calculator 160 can use the signal Z(n) for not using the transmitted signal x(t) as an input for calculating the values of the weights w ₁ to w _k during operation (or x(n)) The operation of calculating and selecting the value of these weights in the case of associated components. This may allow the structure or operation of the echo canceler 101 (or both) to be back using a component associated with the transmitted signal x(t) (or x(n)) that is the input used to calculate the value of the weight. The structure or operation complexity of the wave canceller 101 is small. In addition, the echo canceller 101 can be relatively fast and RF-free without using components associated with the transmitted signal x(t) (or x(n)) as an input for calculating the value of the weight. Loss is less sensitive.

As shown in FIG. 1, echo canceller 101 can include a delay 103 coupled to the transmission path of transmitter 120. Delay 103 may provide a time delay to compensate for other components in the echo estimation path of echo canceller 101 (eg, the path may be between delay τ ₁ and summer 155) (eg, vector modulators 131 and 132 and The delay in summer 155) is used to generate echo cancellation signals (e.g., x ₁ (t) and x ₂ (t)). The value of delay 103 can be selected to ensure that the echo delay is between x ₁ (t) and the delay value of x(t) in x ₂ (t).

Vector modulators 131 and 132 may include similar or identical components. Thus, for the sake of simplicity, only the details of vector modulator 131 are shown in FIG. Vector modulator 131 may include an input configured to receive a signal x (t-τ ₁₎ of the stationary phase shifters 141, 142 and 143, the input signal x (t-τ ₁₎ based on the transmitted signal x (t ) with a delay of τ ₁ . For example, the input signal x(t-τ ₁ ) (the delayed version of the transmitted signal x(t)) may be selected from the tap T=1 of the transmitted signal x(t). Phase shifters 141, 142, and 143 can be configured for fixed phase shifts (eg, 0°, 60°, and 120°, respectively) relative to the transmitted signal x(t). Phase shifters 141, 142, and 143 generate corresponding output signals at their outputs. The output signal can be attenuated by an attenuator unit that can include a variable or stepped attenuator unit. The attenuator unit may include attenuators 151, 152, and 153. Attenuators 151, 152, and 153 can include variable or stepped attenuators. The attenuators 151, 152, and 153 can be controlled by a set of weights w ₁ , w _{2 ,} and w ₃ as shown in FIG. Attenuators 151, 152, and 153 produce an attenuated signal at their output. Each of the attenuated signals corresponds to an output signal of one of phase shifters 141, 142, and 143. The attenuated signal at the output of the attenuator 151, 152 and 153 may be summed by summer 154 to produce signal x ₁ (t), the signal x ₁ (t) of the echo cancellation at the output 101 of One of the signals.

Vector modulator 132 may be configured to receive an input signal x (t-τ _2), the input signal x (t-τ ₂₎ based signal x (t) based on the transmission delay τ _2. For example, the input signal x(t-τ ₂ ) (the delayed version of the transmitted signal x(t)) may be selected from the tap T=2 of the transmitted signal x(t). Vector modulator 132 may include stationary phase shifters, attenuators (eg, variable or stepped attenuators), and sums similar or identical to those of vector modulator 131 shown in FIG. Device. In vector modulator 132, the output signal at the output of the phase shifter can be attenuated by an attenuator unit (e.g., a variable or stepped attenuator unit). An attenuator (eg, a variable or stepped attenuator) in the attenuator unit can be controlled by a set of weights w ₄ , w _{5 ,} and w ₆ . Via the output of the vector modulator 132 of the attenuator the attenuation of the signal may be in the summer by the vector modulator 132 to generate a summed signal x ₂ (t), the signal x ₂ (t) of the echo cancellation Another output signal at the output of the device 101.

Summer 155 can be configured to sum the received signals of signals x ₁ (t) and x ₂ (t) with echo y(t) to produce an echo cancelled signal z(t).

As mentioned above, the weight calculator 160 can use the signal Z(n) for the operation of calculating and selecting the values of the weights w ₁ to w _k . The weight calculator 160 can select the values of the weights w ₁ to w _k by performing an operation of searching for the value of the weight. The search can be minimized based on the cost function of the signal Z(n). The cost function can be expressed as C ( W )= E |{ Z ( t )| ² }= E |{ Y ( t )- W ^T X ( t )| ² (1)

Where Z(t) is the output of the echo canceler 101, y(t) is the received signal containing the echo signal, and X(t) is the vector signal of the transmitted signal with different delays and phase rotations, and W = [w ₁ ... w _K ] ^T is a weight vector. As can be seen in equation (1), the cost function is a quadratic function of the weight vector. Therefore, the local minimum of the cost function is the global minimum of the cost function. Thus, the value of the weights w ₁ to w _k can be selected by searching for weight values that fall within the global minimum of the cost function, which is also the minimum of the power of the signal Z(n). Therefore, the specific value of the weight can be selected by searching for the minimum value of the power of the signal Z(n).

As shown in FIG. 1, a signal Z(n) can be generated from the echo cancel signal z(t) using a path that can include: a band pass filter 161; to modify (eg, amplify) the echo A variable gain amplifier (VGA) 162 that cancels the signal z(t); a downconverter that is used to downconvert the echo cancelled signal z(t) by the VGA 162 to generate a baseband signal And an analog-to-digital converter for converting the echo canceled signal z(t) by the VGA 162 and downconverting it by the down converter 163 to generate the signal Z(n) ( ADC) 164. The weight calculator 160 of the echo canceller 101 may include a periodic measurement unit 165 to measure the power (P) of the signal Z(n) over a certain time interval based on the equation (2).

The operation of VGA 162 may change the power of signal Z(n). Therefore, in order to maintain the value (eg, the true value) of the signal Z(n) used in the calculation of the search weight value, the compensation value as shown in equation (3) may be utilized by unit 166 (eg, 1/ g ² ) to compensate for the power value of the signal Z(n). Therefore, the cost function of the signal Z(n) that compensates for the gain of the VGA 162 can be based on the following equation

Where "g" is defined as the gain of the VGA 162 on a linear scale.

In the operation of calculating and selecting the weight value (as detailed in Figure 2) As described in detail, since it is impossible to obtain an overall average value, the time average of the signal Z(n) which is a digital baseband signal can be performed for a certain period of time. Wireless communication system 100 can communicate with other systems or devices using orthogonal frequency division multiplexing (OFDM) access. In such access, the OFDM signal can be averaged over an OFDM symbol or an integer multiple of OFDM symbols. During the averaging of power, the weights can be fixed.

The weight calculator 160 may also include a weight selection unit 167 configured to select values of the weights w ₁ to w _k based on equation (3), as described in more detail below with respect to FIG. 2 . After the values of the weights w ₁ to w _{k are} selected, they can be applied (at the control inputs of the attenuators of the vector modulators 131 and 132) in the echo canceller 101 for controlling the attenuators (eg, vector tones). 151, 152 and 153) of the transformers 131 and 132.

The selected value of the weight can remain unchanged after it is selected. Alternatively, echo canceller 101 can adjust this value based on some predetermined conditions. For example, echo canceller 101 can include a power monitor 170 configured to monitor the power value of signal Z(n) measured by periodic measurement unit 165. Based on the power monitored value, power monitor 170 may cause echo canceller 101 to adjust the value of the weight (eg, by selecting a new value for the weight). For example, during weight recalibration of echo canceller 101, power monitor 170 may cause periodic measurement unit 165 to be not receiving signals (eg, downlink signals after some predetermined time interval or while wireless communication system 100 is not receiving signals) The power of the signal Z(n) is measured. If the value of the measured power during the measurement exceeds a threshold (eg, a predetermined value), the power monitor 170 may cause the echo canceler 101 to adjust the value of the weight such that the power value may be reduced to an appropriate value. . This allows the weight value to be maintained The optimum value (e.g., the selected value) is to maintain the proper echo cancellation operation performed by the echo canceler 101.

2 is a flow diagram showing a method 200 for operating a wireless communication system including selecting weights to control operation of an attenuator of an echo canceler, in accordance with some embodiments described herein. Method 200 can be performed by wireless communication system 100 of FIG. Accordingly, the echo canceller used in method 200 can include the echo canceller 101 of FIG.

In the method 200, the target weight for the search (e.g., of ₁₆₁ W to FIG w) of the minimum value of each of the generated signal Z (n) (shown in FIG. 1) of the cost function (e.g., topical The value of the minimum value). As described above with reference to Figure 1, because the cost function is a quadratic function of the weight vector, the minimum of the cost function can be associated with a weight, where each of the weights can be negative or positive (along the cost function) X (axis of C (W)). Thus, method 200 can begin at activity 201 and activities 210 through 216 are performed to search for the sign (negative or positive) of each of the weights. By searching for the sign, the method 200 can obtain a starting value for each of the weights that is relatively close to the global minimum. This may allow a faster discovery of the final value of each of the weights (a value that falls within the global minimum). After determining the sign of each of the weights, method 200 can use the start value of the weights for the final value of each of the search weights, as described in activities 220 through 228. Method 200 may end at activity 299 after the final value is found.

To begin searching for the sign, activity 210 may include initializing the weight of the weight (eg, w ₁ to w _{6 of} FIG. 1) such that w _k = w _min , where "k" is the index of the particular weight. In the method 200, assume that the echo canceller of the echo estimation filter attenuator in the path (e.g., attenuators 151, 152 and 153) having a linear scale w _min | w | The dynamic range of w _max , where w _min corresponds to the minimum of the dynamic range and w _max corresponds to the maximum of the dynamic range.

Activity 211 can include defining a difference between w _min and w _max as Δ = w _max - w _min .

Activities 212 through 216 can include performing a decision to control the sign of each of the weights of the attenuators in the echo estimation path of the echo canceller. The value of "K" in activity 212 may be equal to the number of attenuators in the echo estimation path.

Activity 213 may include calculating two values C ₁ (W) and C ₂ (W) based on different values of weights w _k applied to the same attenuator at different time intervals. For example, as shown in activity 213, C ₁ (W) can be calculated using w _k = w _min + Δ/2 applied to a particular attenuator (eg, attenuator 151 in FIG. 1) during a time interval. ). C ₂ (W) can be calculated using w _k =- w _min -Δ/2 applied to the particular attenuator during another time interval. The unit for the echo canceller in method 200 (e.g., 165 in Figure 1) can measure the power of signal Z(n) at these two time intervals to calculate C ₁ (W) and C ₂ (W) The value. During these measurements at a specific weight (e.g., in the FIG. ₁ w 1), the other weights (e.g., w ₂ to w ₆₎ The value may be kept constant.

Activity 214 may include a value based on w _k ( w _min + Δ/2 or - w _min - Δ/2) that results in a smaller value between C ₁ ( W ) and C ₂ ( W ) calculated in activity 213 To set the value of a specific weight (w _k ). For example, activity 214 may set w _k = w _min +Δ/2 (if C ₁ ( W )< C ₂ ( W )) or w _k =− w _min −Δ/2 (if C ₁ ( W )> C ₂ ( W )).

Method 200 may repeat the same operation (eg, perform activities 213 through 216) for each of the weights (eg, each of w ₂ through w ₆ in FIG. 1) until a weight is determined (eg, set) The sign of each of them (for example, - w _min -Δ/2 or w _min +△/2).

After setting the sign of all K weights, method 200 may continue with activities 220 through 228 to perform M iterations to further improve the value of each of the weights to search for the final value of each of the weights. As shown in 223 events at each iteration step m, the iteration is used to calculate the specific value of w _k of the cost function is less than the previous value w _{k (e.g.,} w _{k, old).} Therefore, M iterations are performed with a reduced step. For example, when m=1, activity 223 can calculate the value of C ₁ ( W ) using w _k = w _k,old +Δ/2 ^{m +1} = w _k,old +Δ/4, and use w _k = w _k,old -Δ/2 ^{m +1} = w _k,old -△/4 Calculate the value of C ₂ ( W ). In an iteration below m=2, activity 223 may calculate the value of C ₁ ( W ) using w _k = w _k,old +Δ/2 ^{m +1} = w _k,old +Δ/8, and use w _k = w _k,old -Δ/2 ^{m +1} = w _k,old -△/8 Calculate the value of C ₂ ( W ).

Activity 224 may include w _k based on the smaller value between C ₁ ( W ) and C ₂ ( W ) that results in activity 223 ( w _k = w _k,old +Δ/2 ^{m +1} or w _{k The , old} - Δ/2 ^{m +1} ) value sets the value of the particular weight (w _k ) for a particular iteration. For example, activity 224 may set w _k = w _k,old +Δ/2 ^{m +1} (if C ₁ ( W )< C ₂ ( W )) or set w _k = w _k,old -Δ/2 ^{m +1} (if C ₁ ( W )> C ₂ ( W )).

Thus, during a time interval associated with activities 221 through 228 of the final value of each of the selection weights, method 200 can include applying a plurality of weight values (eg, w _k = w _k,old +Δ/2 ^{m +1} or w _k,old -Δ/2 ^{m +1} , during M iterations) to control the attenuator of the echo canceler. The plurality of values are different from the weight values (e.g., w _min + Δ/2 or w _min - Δ/2) used to calculate C ₁ ( W ) and C ₂ ( W ) in activity 213. Activities 221 through 228 may also include calculating a plurality of values of the cost function when applying a plurality of weight values (eg, calculating C ₁ ( W ) and C ₂ ( W ) in activity 223). For each of the weights, the cost function of signal Z(n) during the time interval associated with activities 220 through 228 is the lowest of a plurality of values of the cost function of signal Z(n) (eg, Global minimum).

Method 200 may repeat the same operation (eg, perform activities 221 through 228) for each of the weights (eg, each of w ₂ through w ₆ in FIG. 1) until a weight is determined (eg, set) The final value of each of them (the value that falls on the global minimum of the cost function).

Method 200 may end at activity 299 after determining the final value of the weight of ownership. Method 200 can select this value and apply it to the echo canceler to control the attenuator of the echo canceler.

As described above, method 200 searches for weights that fall within the global minimum and selects their values for use in the echo canceller. Therefore, by searching for the value of the weight, the optimal value of the weight (for example, the value falling on the global minimum) can be selected. This avoids exhaustive searching and avoids adaptively updating weights. Avoiding such exhaustive search and update weights can improve the seek speed of the echo canceler 101 (e.g., faster search).

In method 200, the final value of the weight applied to the corresponding attenuator in the echo canceller can be fixed. Alternatively, the final value of the weight can be adjusted (eg, during weight recalibration, as described above with reference to FIG. 1). For example, during recalibration (after the selected final value), if the power monitor (eg, power monitor 170 in Figure 1) detects a power value relative to a threshold Method 200 may repeat activities 201 through 299, for example, a change in predetermined value. As an example, if the power value (eg, during weight calibration) is greater than the threshold, method 200 may repeat activities 201 through 299. Method 200 may repeat activities 201 through 299 at intervals that are not expected to be received by the wireless communication system. This is used to avoid the incoming signal being used in power calculations, which may result in inaccurate selection of weight values.

Method 200 can include fewer or more activities than those shown in FIG. For example, method 200 can also include or be included in the operation of wireless communication system 100, a network station, or the wireless communication devices described below with respect to FIGS. 3 and 4, described above with respect to FIG.

As described above, the method 200 can be performed based on the signal Z without using a component associated with the transmitted signal x(t) (or x(n)) as an input for calculating the value of the weight. n) The cost function calculates and selects the operation of the weight value. Thus, method 200 can be referred to as a blind technique for calculating weights. Method 200 may allow the echo canceller used in method 200 to be relatively simple, relatively fast, and less sensitive to RF impairments.

3 shows a wireless communication network 300 including a network station 302 and wireless communication devices 311 and 312, in accordance with some embodiments described herein. Network station 302 can be configured (e.g., assembled) to wirelessly communicate with wireless communication device (WCD) 311 via wireless connection 313 and with WCD 312 via wireless connection 315. Network station 302 and each of WCDs 111 and 112 may include wireless communication system 100 described above with respect to FIG. Accordingly, each of network station 302 and WCDs 111 and 112 may include components and operations similar or equivalent to those described above with respect to FIGS. 1 and 2. For example, network station 302 and each of WCDs 111 and 112 can include echo canceller 101 of FIG. 1 and can be configured to perform echo cancellation, including as described above with respect to FIGS. 1 and 2. The operation for calculating and selecting weights.

In FIG. 3, an example of a wireless communication network 300 includes an Evolved Universal Terrestrial Radio Access Network (EUTRAN) that uses the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard. Additional examples of wireless communication networks 300 include microwave access global interoperability (WiMax) networks, third generation (3G) networks, Wi-Fi networks, and other wireless data communication networks.

Examples of network station 302 include a base station (BS), an enhanced Node B (eNB), an access point (AP), or another type of network station or network device. Network station 302 can be configured to operate based on the 3GPP-LTE standard or other wireless data communication standards.

Examples of WCDs 311 and 312 include user equipment (UE) and terminal equipment (e.g., data terminal equipment). Examples of user equipment and terminal equipment include cellular telephones (eg, smart phones), tablets, electronic readers (eg, e-book readers), notebook computers, laptop computers, desktop computers, personal computers. , servers, personal digital assistants (PDAs), digital cameras, medical devices (eg, heart rate monitors, blood pressure monitors, etc.), televisions, network electrical equipment, set-top boxes (STBs), network routers, networks Road switches, network bridges, parking meters, sensors and other types of devices and equipment.

WCDs 311 and 312 can be configured (eg, configured) to operate in different communication networks, such as 3GPP-LTE networks, WiMax networks, none Line area network (eg WiFi) and other communication networks. 3 shows a wireless communication network 300 that, as an example, includes only two WCDs (eg, WCDs 311 and 312) to communicate with the network station 302. However, wireless communication network 300 can include more than two WCDs.

Network station 302 can have both transmit (Tx) and receive (Rx) capabilities (STR capabilities) such that it can operate in STR mode to simultaneously and (eg, in parallel) transmit and receive signals (eg, radio frequency (RF) signals) ). Network station 302 can include an RF transceiver with full duplex capability to simultaneously transmit and receive signals. For example, network station 302 can transmit downlink (DL) signals to WCD 311 while network station 302 receives uplink (UL) signals from WCD 312. In another example, network station 302 can transmit DL signals to WCD 312 while network station 302 receives UL signals from WCD 311.

4 shows a block diagram of a WCD 400 including an echo canceller 401, in accordance with some embodiments described herein. WCD 400 can include components of wireless communication system 100 (Fig. 1). As shown in FIG. 4, the WCD 400 can also include antennas 402 and 404, a transceiver 405 including a receiver 410 and a transmitter 420, a controller 415, and a memory 430. The echo canceller 401, the receiver 410, and the transmitter 420 may correspond to the echo canceller 101, the receiver 110, and the transmitter 120 of FIG. 1, respectively. Accordingly, echo canceller 401, receiver 410, and transmitter 420 can be configured to operate in a manner similar or identical to the manner of echo canceller 101, receiver 110, and transmitter 120 of FIG.

The WCD 400 in FIG. 4 may also include a keyboard, a display (eg, an LCD screen including a touch screen), a non-electric memory (eg, a universal serial bus (USB) port), a speaker, and other actions. In the device component One or more.

Controller 415, echo canceller 401, or both may be configured (e.g., assembled) to perform the operations described above with respect to Figures 1-3. For example, controller 415 and echo canceller 401 can be configured to perform echo cancellation operations, including operations for calculating and selecting weights as described above with respect to FIGS. 1 and 2.

Controller 415 can be configured (e.g., assembled) to provide processing and control functionality for WCD 400, including at least a portion of the echo cancellation operations described above with respect to Figures 1-3. Controller 415 can include one or more processors, which can include one or more central processing units (CPUs), one or more graphics processing units (GPUs), or one or more CPUs and one or more GPUs combination.

Memory 430 can include an electrical memory, a non-electrical memory, or a combination of both. The memory 430 can store instructions (eg, a firmware program, a software program, or a combination of both). Controller 415 can execute instructions in memory 430 to cause WCD 400 to perform operations, such as echo cancellation operations, including operations for selecting weights performed by wireless communication system 100 or as described herein with respect to Figures 1-2 Method 200.

Antennas 402 and 404 may include one or more directional or omnidirectional antennas including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmitting RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures can be used. In these embodiments, each aperture can be considered to be a separate antenna. Antennas 402 and 404 can be configured to support multiple input and multiple output (MIMO) communications. In some MIMO embodiments, antennas 402 and 404 may have The separation is effected to benefit from the spatial diversity and different channel characteristics that can be caused between the antennas 402 and 404 and the antenna of the transmission station. In some MIMO embodiments, antennas 402 and 404 can be separated to 1/10 or more of multiple wavelengths.

4 shows a WCD 400 including a transceiver 405 and two antennas 402 and 404 as an example. The number of transceivers 405 and antennas 402, 404 can vary. Controller 415 and transceiver 405 can be configured to operate in different communication networks, such as 3GPP-LTE networks, WiMax networks, wireless local area networks (e.g., WiFi), and other communication networks.

Although WCD 400 is shown as having a number of separate functional elements, one or more of the functional elements can be combined and implemented by a combination of software combination elements, such as processing elements including digital signal processors (DSPs) and/or Or other hardware components. For example, some components may include one or more microprocessors, DSPs, special application integrated circuits (ASICs), radio frequency integrated circuits (RFICs), and various hardware and functions for performing at least the functions and operations described herein. a combination of logic circuits. In some embodiments, a functional element may refer to one or more processes operating on one or more processing elements.

Embodiments may be practiced in one or a combination of hardware, firmware, and software. Embodiments can also be implemented as instructions (eg, firmware, software, or a combination of both) stored on a computer readable storage medium, which can be read and executed by at least one processor to perform the operations described herein. operating. The computer readable storage medium can include any non-transitory mechanism (e.g., non-transitory computer readable medium) for storing information (e.g., instructions) in a form readable by a machine (e.g., a computer). Examples of computer readable storage media may include read only memory (ROM), random access memory (RAM), disk storage media, Optical storage media, flash memory devices, and other storage devices and media. In such embodiments, one or more processors of WCD 400 may be configured with instructions to perform the operations described herein.

Additional comments and examples

Example 1 includes the subject matter (such as a device, device, or machine) including an echo canceller for a wireless communication system, the echo canceler comprising: a phase shifter for generating an output signal in the phase shifters Each of the output signals generating one of the output signals, each of the output signals having a phase shift relative to one of the transmitted signals; an attenuator unit (eg, a variable or stepped attenuator unit) And ???attenuating the output signal of each of the phase shifters based on the weights to generate an attenuated signal, each of the attenuated signals corresponding to one of the phase shifters The output signal; a weighting calculator for performing the selection of the equal weights without using components associated with the transmitted signals as inputs for calculating the values of the weights And an at least one summer for summing the attenuated signals with the received signals comprising one of the echo signals to generate an echo canceled signal.

In Example 2, the subject matter of Example 1 can optionally include, wherein the weighting calculator is configured to perform the selecting of the weights based at least in part on a cost function that generates a digital signal based on the echo cancelled signal. The operation.

In Example 3, the subject matter of Example 1 may optionally include, wherein the weight calculator is configured to perform the operation for selecting the weights based on the following equations

Where Z(n) represents the digital signal, W represents a weight vector including one of the weights, and g represents a gain of a variable gain amplifier located on one of the paths used to generate the digital signal.

In Example 4, the subject matter of Example 1 may optionally include, wherein the weight calculator is configured to: generate a signal based on the echo cancelled signal; based on applying to one of the attenuator units during a first time interval A first value of a weight of the attenuator (eg, a variable or stepped attenuator) calculates a first value of a cost function of the signal; based on the weight applied to the attenuator during a second time interval One of the second values calculates a second value of the cost function of the signal; selecting one of the first and second values of the weight starting value equal to the weight; and performing the beginning based on the weight The value searches for one of the third values of the weight operation such that when the third value of the weight is applied to the attenuator during a third time interval, the cost function of the signal is during the third time interval A third value is less than each of the first and second values of the cost function of the signal.

In Example 5, the subject matter of Example 1 may optionally include, wherein the echo canceller is included in a User Equipment (UE).

In Example 6, the subject matter of Example 1 may optionally include, wherein the echo canceler is included in one of a base station and an enhanced Node B (eNB).

The subject matter of the example 7 includes a wireless communication system including: a receiver for receiving a signal containing one of the echo signals; a transmitter for transmitting a transmission signal, and an echo canceller, comprising: a first vector modulator for generating a first output signal from a sum of one of the first plurality of signals, The first plurality of signals are attenuated based on a first set of weights, each of the first plurality of signals having a phase shift relative to one of the first delayed versions of the transmitted signal; a second vector a modulator for generating a second output signal from a sum of one of the second plurality of signals, the second plurality of signals being attenuated based on the second set of weights, each of the second plurality of signals Having a phase shift relative to one of the second delayed versions of the transmitted signal; a summer for summing the first and second output signals with the received signal containing the echo signal Generating an echo cancel signal; and a weight calculator configured to perform a first selection for the first value based on a power of one of the digital signals associated with the echo cancel signal And one of the values of the second set of weights.

In Example 8, the subject matter of Example 7 may optionally include, wherein the echo canceller further includes a power measuring unit to measure the power of the digital signal over a period of time to obtain the power of the digital signal. value.

In Example 9, the subject matter of Example 8 may optionally include, wherein the echo canceller further comprises: a variable gain amplifier for modifying the echo canceled signal; and an analog to digital converter for use The echo cancelled signal is converted to generate the digital signal after the echo cancelled signal is modified by the variable gain amplifier.

In Example 10, the subject matter of Example 9 may include, as appropriate, The echo canceller is configured to compensate for the value of the power of the digital signal with a compensation value based on the gain of the variable gain amplifier.

In Example 11, the subject matter of Example 7 can optionally include, further comprising a power monitor to monitor a value of one of the powers of the digital signal after selecting the equivalent of the first and second sets of weights, and The echo canceller performs an additional operation for adjusting the values of the first and second sets of weights if the value of the power of the digital signal exceeds a threshold.

In Example 12, the subject matter of Example 7 can be optionally included, wherein the receiver and transmitter are included in one of the wireless communication system full duplex transceivers.

In Example 13, the subject matter of Example 7 may optionally include wherein the receiver is configured to receive a downlink signal.

In Example 14, the subject matter of Example 7 can be optionally included, wherein the receiver is configured to receive an uplink signal.

The subject matter of example 15 includes a method for operating a wireless communication system, the method comprising: calculating the signal based on a first value applied to a weight in the echo canceler during a first time interval a first value of a cost function; calculating a second value of the cost function of the signal based on a second value of the weight applied to the echo canceler during a second time interval; selecting the weight a start value equal to one of the first and second values of the weight; and performing an operation of searching for one of the third values of the weight based on the start value of the weight such that the third value of the weight When applied to the echo canceler during a third time interval, The cost function of the signal during the third time interval has a third value that is less than each of the first and second values of the cost function of the signal.

In Example 16, the subject matter of Example 15 can optionally include, wherein the selecting the starting value of the weight comprises: if the first value of the cost function of the signal is less than the second value of the cost function of the signal, Selecting the starting value of the weight equal to the first value of the weight; and if the first value of the cost function of the signal is greater than the second value of the cost function of the signal, selecting the starting value of the weight Equal to the second value of the weight.

In Example 17, the subject matter of Example 15 is optionally included, wherein the cost function of the signal is

Where Z(n) represents the signal based on the output signal, where W represents a weight vector comprising the weight and g represents a gain of a variable gain amplifier located on one of the paths used to generate the signal.

In Example 18, examples of the subject matter 15 of optionally include wherein wherein the first value is the weight of the weights is equal to w _min + △ / 2, and the second value is the weight of the weights is equal to w _min - △ / 2, where △ = w _max - w _min , where w _min corresponds to a minimum of a dynamic range of an attenuator (eg, a variable or step attenuator) in an echo estimation path in the echo canceler, and wherein w _Max corresponds to one of the maximum values of the dynamic range.

In Example 19, the subject matter of Example 15 can optionally include, wherein the third value of the weight falls within a global minimum of one of the cost functions of the signal.

In Example 20, the subject matter of Example 15 can optionally include wherein the performing the third value of the search weight comprises applying a plurality of values of the weights to control the attenuator of the echo canceler (eg, a variable or stepped attenuator) wherein the plurality of values are different from the first and second values of the weight; and calculating a plurality of values of the cost function when the plurality of values of the weight are applied, Wherein the cost function of the signal is the lowest value of the plurality of values of the cost function of the signal during the third time interval.

In Example 21, the subject matter of Example 15 can optionally include, further comprising: calculating the cost function of the signal based on a first value applied to one of the additional weights in the echo canceler during a fourth time interval a third value, wherein the fourth time interval occurs after the first and second time intervals and before the third time interval; based on being applied to the echo canceler during a fifth time interval a second value of the additional weight calculating a fourth value of the cost function of the signal, wherein the fifth time interval occurs after the first and second time intervals and before the third time interval; If the third value of the cost function is less than the fourth value of the cost function, selecting one of the additional weights is equal to the first value of the additional weight; if the third value of the cost function is greater than the cost function The fourth value, selecting one of the additional weights starting value equal to the second value of the additional weight; and performing an operation of searching for one of the third values of the additional weight, such that the third of the additional weights When the value is applied to the echo canceller during a sixth time interval, the cost function of the signal during the sixth time interval has a fifth value that is less than the cost function of the signal. Each of the third and fourth values.

In Example 22, the subject matter of Example 15 may optionally include wherein the starting value of the additional weight is selected to include: if the third value of the cost function is less than the fourth value of the cost function, then selecting the additional weight The start value is equal to one of the first values of the additional weight; and if the third value of the cost function is greater than the fourth value of the cost function, selecting the start value of the additional weight is equal to the second of the additional weight value.

The subject matter of the example 23 includes a computer readable storage medium for storing information, the information being executed such that a wireless communication device: generates a signal based on an output signal from an echo canceller; based on a first A first value applied to one of the weights in the echo canceler during the time interval calculates a first value of a cost function of the signal; based on the application to the echo canceller during a second time interval a second value of the weight calculating a second value of the cost function of the signal; selecting one of the first and second values of the weight starting value equal to the weight; and performing the weighting based on the weight The start value searches for one of the third values of the weight such that when the third value of the weight is applied to the echo canceler during a third time interval, the cost function of the signal is at the third A third value during one of the time intervals is less than each of the first and second values of the cost function of the signal.

In Example 24, the subject matter of Example 23 can optionally include, wherein if the first value of the cost function of the signal is less than the second value of the cost function of the signal, then the starting value of the weight is selected as Equal to the first value of the weight, and if the first value of the cost function of the signal is greater than The second value of the cost function of the signal, the starting value of the weight is selected to be equal to the second value of the weight.

In Example 25, the subject matter of Example 23 may optionally include wherein the cost function of the signal is

Where Z(n) represents the signal based on the output signal, where W represents a weight vector comprising the weight and g represents a gain of a variable gain amplifier located on one of the paths used to generate the signal.

The subject matter of Examples 1 to 25 can be combined in any combination.

The abstract is provided to comply with the requirements of 37 C.F.R. Section 1.72(b) which will allow the reader to determine the essence of the technical disclosure and the summary of the points. It is submitted with the understanding that it will not be used to limit or explain the scope or meaning of the scope of the patent application. The scope of the following patent application is hereby incorporated by reference in its entirety in its entirety in its entirety in its entirety in the in the in the

100‧‧‧Wireless communication system

101‧‧‧ Echo canceller

102‧‧‧Antenna

103‧‧‧Delay

110‧‧‧ Receiver

111‧‧‧Low noise amplifier

112, 163‧‧ ‧ down converter

113, 164‧‧‧ analog to digital converter

120‧‧‧Transporter

121‧‧‧Digital to analog converter

122‧‧‧Upconverter

123‧‧‧Power Amplifier

131, 132‧‧‧ vector modulator

141, 142, 143‧‧‧ stationary phase shifter

151, 152, 153‧‧‧ attenuators

154, 155‧‧‧sumer

160‧‧‧weight calculator

161‧‧‧Bandpass filter

162‧‧•Variable Gain Amplifier

165‧‧‧Periodic measurement unit

Unit 166‧‧‧

167‧‧‧ weight selection unit

170‧‧‧Power monitor

Claims (25)

An echo canceler for use in a wireless communication system, the echo canceler comprising: a phase shifter for generating an output signal, each of the phase shifters generating one of the output signals Each of the output signals has a phase shift relative to one of the transmitted signals; an attenuator unit for attenuating the output signal of each of the phase shifters based on the weights to Generating an attenuated signal, each of the attenuated signals corresponding to the output signal of one of the phase shifters; a weighting calculator for not using and acting as a calculation for the In the case of a component associated with the transmitted signal of the input of the value of the weight, an operation for selecting the value for the weights is performed; and at least one summer for the attenuated signal A summation is performed with a received signal containing one of the echo signals to produce an echo canceled signal. The echo canceller of claim 1, wherein the weight calculator is configured to perform the selecting of the weights based at least in part on a cost function of a digital signal generated based on the echo cancelled signal operating. An echo canceller as claimed in claim 2, wherein the weight calculator is configured to perform the operation for selecting the weights based on the following equation Where Z(n) represents the digital signal, W represents a weight vector including one of the weights, and g represents a gain of a variable gain amplifier located on one of the paths used to generate the digital signal. The echo canceller of claim 1, wherein the weight calculator is configured to: generate a signal based on the echo cancelled signal; based on a one of the attenuators applied to the attenuator unit during a first time interval Calculating a first value of a cost function of the signal by a first value; calculating the cost function of the signal based on a second value of the weight applied to the attenuator during a second time interval a second value; selecting one of the first and second values of the weight to be equal to one of the first and second values of the weight; and performing one of the third values based on the starting value of the weight to search for one of the weights ??? such that when the third value of the weight is applied to the attenuator during a third time interval, the cost function of the signal during the third time interval has a third value less than the cost function of the signal Each of the first and second values. The echo canceller of claim 1, wherein the echo canceller is included in a user equipment (UE). The echo canceller of claim 1, wherein the echo canceller is included in one of a base station and an enhanced Node B (eNB). A wireless communication system comprising: a receiver for receiving a signal containing an echo signal; a transmitter for transmitting a transmitted signal, and an echo canceler comprising: a first a vector modulator for generating a first output signal from a sum of one of the first plurality of signals, the first plurality of signals being attenuated based on the first set of weights, each of the first plurality of signals a signal having a phase shift relative to one of the first delayed versions of the transmitted signal; a second vector modulator for generating a second output signal from a sum of the second plurality of signals, A second plurality of signals are attenuated based on a second set of weights, each of the second plurality of signals having a phase shift relative to one of the second delayed versions of the transmitted signal; a summer, And summing the first and second output signals with the received signal containing the echo signal to generate an echo cancel signal; and a weight calculator configured to perform for The echo is associated with one of the digital signals associated with the cancellation signal One of a number of power values for selecting such a first and a second set of weights, one weight value operation. The wireless communication system of claim 7, wherein the echo canceller further comprises a power measuring unit to measure the power of the digital signal over a period of time to obtain the value of the power of the digital signal. The wireless communication system of claim 8, wherein the echo canceller further comprises: a variable gain amplifier for modifying the echo canceled signal; and an analog to digital converter for the echo The cancelled signal is modified by the variable gain amplifier to convert the echo cancelled signal to produce the digital signal. The wireless communication system of claim 9, wherein the echo canceller is configured to compensate for the value of the power of the digital signal with a compensation value based on the gain of the variable gain amplifier. The wireless communication system of claim 7, further comprising a power monitor to monitor a value of one of the powers of the digital signal after selecting the equal values of the first and second sets of weights, and wherein the digital signal is The echo canceller performs an additional operation for adjusting the values for the first and second sets of weights if the value of the power exceeds a threshold. The wireless communication system of claim 7, wherein the receiver and transmitter are included in a full duplex transceiver of the wireless communication system. A wireless communication system as claimed in claim 7, wherein the receiver is configured to receive a downlink signal. A wireless communication system as claimed in claim 7, wherein the receiver is configured to receive an uplink signal. A method for echo cancellation of a wireless communication system, the method comprising: Generating a signal based on an output signal from an echo canceler; calculating a first one of the cost functions of the signal based on a first value applied to a weight in the echo canceler during a first time interval a second value of the cost function of the signal is calculated based on a second value of the weight applied to the echo canceller during a second time interval; selecting one of the weights to start the value is equal to the weight And one of the first and second values; and performing an operation of searching for one of the third values of the weight based on the starting value of the weight such that the third value of the weight is at a third time interval When applied to the echo canceller, the cost function of the signal during which the third value is less than each of the first and second values of the cost function of the signal . The method of claim 15, wherein the selecting the starting value of the weight comprises: if the first value of the cost function of the signal is less than the second value of the cost function of the signal, selecting the starting value of the weight And the first value equal to the weight; and if the first value of the cost function of the signal is greater than the second value of the cost function of the signal, selecting the starting value of the weight to be equal to the weight The second value. The method of claim 15, wherein the cost function of the signal is Where Z(n) represents the signal based on the output signal, where W represents a weight vector comprising the weight and g represents a gain of a variable gain amplifier located on one of the paths used to generate the signal. The method of claim 15, wherein the first value of the weight is equal to w _min + Δ/2, and the second value of the weight is equal to w _min - Δ/2, where Δ = w _max - w _min , where w _Min corresponds to a minimum of the dynamic range of one of the attenuators in an echo estimation path in the echo canceler, and wherein w _max corresponds to one of the maximum values of the dynamic range. The method of claim 15, wherein the third value of the weight falls within a global minimum of one of the cost functions of the signal. The method of claim 15, wherein the performing the third value of the search weight comprises: applying a plurality of values of the weights to control the attenuator of the echo canceler, wherein the plurality of values are different from the The first and second values of the weight; and calculating a plurality of values of the cost function when the plurality of values of the weight are applied, wherein the value of the cost function of the signal during the third time interval is One of the plurality of values of the cost function of the signal. The method of claim 15, further comprising: calculating a third value of the cost function of the signal based on a first value applied to one of the additional weights in the echo canceler during a fourth time interval, wherein The fourth time interval occurs after the first and second time intervals and before the third time interval; Calculating a fourth value of the cost function of the signal based on a second value of the additional weight applied to the echo canceller during a fifth time interval, wherein the fifth time interval occurs at the first And after the second time interval and before the third time interval; if the third value of the cost function is less than the fourth value of the cost function, selecting one of the additional weights starting value to be equal to the additional weight The first value; if the third value of the cost function is greater than the fourth value of the cost function, selecting the starting value of the additional weight to be equal to the second value of the additional weight; and performing the search for the additional One of the third values of the weight operation, such that when the third value of the additional weight is applied to the echo canceller during a sixth time interval, the cost function of the signal is during the sixth time interval One of the fifth values is less than each of the third and fourth values of the cost function of the signal. The method of claim 15, wherein the selecting the starting value of the additional weight comprises: if the third value of the cost function is less than the fourth value of the cost function, selecting the starting value of the additional weight to be equal to the additional One of the first value of the weight; and if the third value of the cost function is greater than the fourth value of the cost function, the starting value of the additional weight is selected to be equal to the second value of the additional weight. A computer readable storage medium for storing information, the information being executed Having a wireless communication device to: generate a signal based on an output signal from an echo canceler; calculate the signal based on a first value applied to a weight in the echo canceler during a first time interval a first value of one of the cost functions; calculating a second value of the cost function of the signal based on a second value of the weight applied to the echo canceler during a second time interval; selecting the weight One of the start values is equal to one of the first and second values of the weight; and performing an operation of searching for one of the third values of the weight based on the start value of the weight such that the weight is When the three values are applied to the echo canceller during a third time interval, the cost function of the signal during the third time interval is such that the third value is less than the first of the cost functions of the signal. And each of the second values. The computer readable storage medium of claim 23, wherein if the first value of the cost function of the signal is less than the second value of the cost function of the signal, the starting value of the weight is selected to be equal to the The first value of the weight, and if the first value of the cost function of the signal is greater than the second value of the cost function of the signal, the starting value of the weight is selected to be equal to the weight of the weight Two values. The computer readable storage medium of claim 23, wherein the cost function of the signal is Where Z(n) represents the signal based on the output signal, where W represents a weight vector comprising the weight and g represents a gain of a variable gain amplifier located on one of the paths used to generate the signal.