JP5123940B2 - Wireless receiver - Google Patents

Description

  The present invention relates to a radio receiver and a method of operating a radio receiver.

  In current mobile cellular standards and technologies such as GSM (pan-European digital mobile communication system) and WCDMA (Wideband Code Division Multiple Access), attention is gradually shifting from circuit-switched, voice-centric use to packet-switched data traffic. . Along with this, the increase in data rate (data transfer rate) has resulted in additions to standards and technologies such as GSM EDGE (high-speed data rate for expansion) and WCDMA HSDPA (high-speed downlink packet access). . As data rates increase, wireless transceiver circuitry becomes more complex. For example, the requirement for signal purity in the transmit / receive circuitry increases to meet the required high data rate.

  A mechanism that makes reception at a high data rate more difficult than reception at a low data rate is that the effective energy per bit of transmission information decreases as the data rate increases. This increases the demand for signal purity in the transmit / receive circuitry. Conventional solutions that improve signal purity when bit-by-bit energy is reduced are radios that meet very stringent requirements such as noise figure, frequency and timing drift, phase noise, image rejection and providing a DC offset to the received signal. Is to design the transceiver. Thus, the higher the data rate, the greater the complexity of the wireless transceiver. The problem with this type of conventional solution is that the resulting network occupies more chip area, resulting in a further increase in cost. Also, the power consumption of such a network is relatively high, and as a result, the battery operating time is shortened. Usually, the maximum achievable data rate is relatively rarely used, but their negative side effects are always present. The reason is that general users occasionally use high data rates. Another reason is that the maximum data rate usually requires very suitable radio conditions that can be found within the line of sight of the base station.

  The objective is to provide a wireless receiver with reduced complexity.

According to a first aspect, a method for operating a wireless receiver is provided. The wireless receiver is configured to receive data via the communication channel in the first mode or the second mode. The second mode facilitates receiving data at a faster data rate than the first mode.

  The method includes determining a quality condition for the communication channel. The method further includes determining whether the communication channel facilitates operation in the second mode based on the quality condition. The method further includes evaluating at least one configuration condition. One of the at least one configuration condition is that the communication channel is determined to facilitate operation in the second mode. Further, the method configures the wireless receiver to operate in the second mode when all of the at least one configuration condition is met, or otherwise operates the wireless receiver in the first mode. Including configuring.

  Configuring the wireless receiver may include configuring an automatic gain control loop of the wireless receiver.

  Configuring the wireless receiver to operate in the second mode may include locking the automatic gain control unit of the automatic gain control loop.

  Configuring the wireless receiver to operate in the first mode may include enabling a DC block unit of the automatic gain control loop. Configuring the wireless receiver to operate in the second mode may include disabling the DC block unit.

  Configuring the wireless receiver to operate in the first mode may include setting a cutoff frequency of the filter of the DC block unit to a first value. Configuring the wireless receiver to operate in the second mode may include setting a cutoff frequency of the filter to a second value. The first value may be greater than the second value.

  The quality condition may be a signal to interference ratio of the communication channel. Determining whether the communication channel facilitates operation in the second mode includes determining that the communication channel facilitates operation in the second mode if the signal to interference ratio exceeds a threshold. Or may include determining otherwise that the communication channel does not facilitate operation in the second mode.

  The method determines whether the received data is expected to be transmitted over the communication channel at any data rate at which data is easily received in the second mode rather than the first mode. It may further include determining based on control data received via the network. One of the at least one configuration condition is that received data is transmitted via a communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode. It may be expected.

  Determining whether the received data is expected to be transmitted over the communication channel at the arbitrary data rate at which data reception is facilitated in the second mode rather than the first mode, Deriving the number of data packet channelization codes used for the received data from the control data may be included. Whether the received data is expected to be transmitted over the communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode is determined by the data packet channel. The determination may be made based on the number of customization codes.

  Determining whether the received data is expected to be transmitted over the communication channel at the arbitrary data rate at which data reception is facilitated in the second mode rather than the first mode, Deriving the modulation scheme used for the received data from the control data. Whether the received data is expected to be transmitted through the communication channel at the arbitrary data rate at which data reception is easily performed in the second mode instead of the first mode depends on the modulation scheme. It may be determined based on.

  Determining whether the received data is expected to be transmitted over the communication channel at the arbitrary data rate at which data reception is facilitated in the second mode rather than the first mode, Deriving from the control data the coding rate used for the received data may be included. Whether the received data is expected to be transmitted over a communication channel at the arbitrary data rate at which data reception is facilitated in the second mode rather than the first mode is determined by the encoding rate. It may be determined based on.

  The communication channel may be, for example, a high speed downlink packet access communication channel or an orthogonal frequency division multiplex communication channel.

  According to a second aspect, a computer program product includes the computer program code for performing the method when the computer program code is executed by an electronic device having computer functionality.

  According to a third aspect, a computer readable medium stores a computer program product comprising said computer program code for performing the method when the computer program code is executed by an electronic device having computer functionality.

According to a fourth aspect, a wireless receiver configured to receive data over a communication channel in a first mode or a second mode is provided. The second mode facilitates receiving data at a faster data rate than the first mode.

  The wireless receiver comprises a signal processing unit configured to determine a quality condition of the communication channel. The wireless receiver further comprises a control unit configured to determine based on the quality condition whether the communication channel facilitates operation in the second mode. The control unit is further configured to evaluate at least one configuration condition. One of the at least one configuration condition is that the communication channel is determined to facilitate operation in the second mode. Further, the control unit configures the wireless receiver to operate in the second mode when all of the at least one configuration condition is satisfied, or otherwise operates the wireless receiver in the first mode. It is comprised so that it may comprise.

  The wireless receiver may comprise an automatic gain control loop. The control unit may be configured to constitute an automatic gain control loop.

  The automatic gain control loop may comprise a variable gain amplifier and an automatic gain control unit configured to control the gain of the variable gain amplifier. The control unit may be configured to lock the automatic gain control unit in the second mode.

  The automatic gain control loop may comprise a DC block unit.

  The control unit may be configured to enable the DC block unit in the first mode and disable the DC block unit in the second mode.

  The DC block unit may include a filter. The control unit may be configured to set the cutoff frequency of the filter to the first value in the first mode. The control unit may be configured to set the cutoff frequency to a second value in the second mode. The first value may be greater than the second value.

  The quality condition may be a signal to interference ratio of the communication channel. The control unit may be configured to determine that the communication channel facilitates operation in the second mode if the signal to interference ratio exceeds a threshold.

  The signal processing unit may be further configured to extract control data from the received signal. The control unit controls whether the received data is expected to be transmitted over the communication channel at any data rate at which data is easily received in the second mode rather than the first mode. It may be further configured to make a determination based on the data. One of the at least one configuration condition is that received data is transmitted via a communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode. It may be expected.

  The control unit may be configured to derive from the control data the number of data packet channelization codes used for the received data. The control unit determines whether the received data is expected to be transmitted over a communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode. It may be further configured to determine based on the number of data packet channelization codes.

  The control unit may be configured to derive from the control data the modulation scheme used for the received data. The control unit determines whether the received data is expected to be transmitted over a communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode. It may be further configured to determine based on the modulation scheme.

  The control unit may be configured to derive from the control data the coding rate used for the received data. The control unit determines whether the received data is expected to be transmitted over a communication channel at the arbitrary data rate at which data is easily received in the second mode rather than the first mode. It may be further configured to determine based on the encoding rate.

  The communication channel may be, for example, a high speed downlink packet access communication channel or an orthogonal frequency division multiplex communication channel.

  According to a fifth aspect, the communication unit comprises a radio receiver. The communication unit may be, for example, a portable or handheld mobile radio communication unit, a mobile radio terminal, a mobile phone, a pager, a communicator, an electronic organizer or a smartphone.

  Further embodiments of the invention are defined in the dependent claims.

  It should be noted that the term “comprises / comprising” as used herein is used to identify the presence of a described feature, number, step or component, but one or more It does not exclude the presence or addition of other features, numbers, steps, components or collections thereof.

Further objects, features and advantages of embodiments of the present invention will become apparent upon reading the following detailed description with reference to the accompanying drawings.
1 is a schematic diagram showing a mobile communication unit and a base station. It is a block diagram which shows the radio receiver which concerns on one Embodiment. , , It is a block diagram which shows embodiment of DC block unit. 2 is a flowchart illustrating one embodiment of a method for operating a wireless receiver. FIG. 5 is a flowchart illustrating one embodiment of one step of the flowchart of FIG. FIG. 5 is a flowchart illustrating another embodiment of one step of the flowchart of FIG.

  FIG. 1 illustrates an environment in which the present invention may be applied. A mobile communication unit 1 such as a mobile phone communicates with a radio base station 2 via a communication channel 3. The communication channel 3 may be, for example, a wideband code division multiple access (WCDMA) communication channel. An example of WCDMA is used as an example in this description. However, the present invention is not limited to WCDMA, and may be applied to other types of communication environments, and may be applied to examples other than the example shown in FIG. For example, the present invention is applicable in orthogonal frequency division multiplexing (OFDM) systems such as the proposed 3GPP Long Term Evolution system.

  High speed downlink packet access (HSDPA) is an addition to WCDMA technology. HSDPA specifies a number of different data rates. HSDPA includes a high-speed physical downlink shared channel (HS-PDSCH) that includes actual data traffic and a high-speed shared control channel (HS-SCCH) that includes control data related to reception and demodulation methods of data transmitted on the HS-PDSCH. Includes a collection of various physical downlink channels to include.

  The communication channel 3 may include a plurality of physical channels as referred to herein. For example, this may include physical channels for control data such as HS-SCCH for HSDPA and physical channels for data traffic such as HS-PDSCH for HSDPA, as well as various other uplink and downlink physical channels. Accordingly, in this document, data received or transmitted via any such physical channel is referred to as data received or transmitted via communication channel 3.

  The maximum data rate available with HSDPA is only used under certain conditions of the communication channel 3. An example of such a specific condition is that communication channel 3 is a channel such as an additive white Gaussian noise (AWGN) channel with relatively little noise and interference. For example, in order to facilitate a data rate of 10 Mbit / s or more with HSDPA, a signal-to-interference ratio (SIR) greater than 15 dB is required.

  Under certain channel conditions that allow the use of the maximum data rate, the achievable data rate is usually limited by signal degradation that occurs in the receiver circuitry. Under low quality channel conditions that only allow the use of low data rates, the achievable data rates are usually limited by signal degradation occurring in the communication channel 3, for example due to multipath fading and external interference. These facts are utilized in the embodiments described below. Under certain channel conditions that allow the use of the maximum data rate, the radio receiver 4 (FIG. 2) may be configured, for example, by reconfiguring, enabling and / or disabling parts of the radio receiver. . Said part of the radio receiver 4 may be a part used under low quality channel conditions to compensate for signal degradation occurring in the communication channel 3. By configuring the wireless receiver 4, signal degradation occurring in the wireless receiver network is reduced. Therefore, by configuring the wireless receiver 4, the wireless receiver 4 is further suitable for receiving data at the maximum data rate. In describing specific embodiments, examples of configurations that may be implemented are given.

FIG. 2 is a block diagram illustrating one embodiment of a wireless receiver 4 that includes an automatic gain control (AGC) loop 30. The wireless receiver 4 is configured to receive data via the communication channel 3 in the first mode or the second mode. The second mode facilitates receiving data at a faster data rate than the first mode. The radio receiver 4 may be included in the mobile communication unit 1 (FIG. 1), for example.

  In the embodiment of FIG. 2, the AGC loop 30 is configured to stabilize the signal level of the received signal inside the wireless receiver 4. The signal level may be, for example, an average power level. According to HSDPA embodiments, the average power level may be an average power level over one or more HSDPA time slots, such as one, two, or three time slots, which are non-limiting examples.

  In the embodiments described herein, the first mode is a mode that may be used under relatively low quality conditions of the communication channel. In the first mode, the components of the wireless receiver 4 are configured to compensate for signal degradation occurring in the channel.

  On the other hand, the second mode is a mode that may be used under relatively appropriate channel conditions. In the second mode, the components of the wireless receiver 4 are configured to reduce signal degradation caused by the components themselves as compared to operation in the first mode. Using the second mode under relatively low quality channel conditions may reduce the robustness of the receiver compared to using the first mode. Thus, according to some embodiments, the second mode should only be used when the communication channel 3 facilitates operation in the second mode.

  According to one embodiment of HSDPA, the data rate that is easily performed in the second mode rather than the first mode is a data rate of 10 Mbit / s or more. According to another embodiment of HSDPA, the data rate easily performed in the second mode rather than the first mode includes only the maximum data rate in HSDPA (14 Mbit / s). In other embodiments, other data rates may be facilitated in the second mode rather than the first mode. Their data rates may vary between various applications and receiver implementations. Experiments such as simulation and measurement may require determining the data rate that is easily performed in the second mode rather than the first mode and determining channel conditions that facilitate operation in the second mode. is there.

  In the embodiment of FIG. 2, the wireless receiver 4 comprises a front end (FE) unit 40. The AGC loop 30 includes a variable gain amplifier (VGA) 41 operably connected to the output of the FE unit 40 and a DC block unit 42 operably connected to the output of the VGA 41. In addition, AGC loop 30 includes an analog-to-digital converter (ADC) 43 operably connected to the output of DC block unit 42 and a digital low-pass (LP) filter configured to filter the digital output signal of ADC 43. 44.

  The output of the LP filter 44 is connected to an AGC unit 45 included in the AGC loop 30. The output of the LP filter 44 is further connected to a signal processing (SP) unit 46 included in the wireless receiver 4.

  The wireless receiver 4 further comprises a control unit (CU) 47 configured to receive information from the SP unit 46. The CU 47 is further configured to configure the wireless receiver 4 to operate in the first mode or the second mode based on information received by the CU 47 from the SP unit 46.

  Each of the AGC unit 45, the SP unit 46, and the CU 47 may be realized by, for example, hardware, software, or a combination thereof. For example, each of the units may be implemented by a programmable hardware unit such as a processor, an application specific hardware unit, or a combination thereof.

  As shown in FIG. 2, the DC block unit 42 may include a filter 42a such as a high-pass (HP) filter or a band-pass (BP) filter.

  Next, the functionality of the various blocks of the wireless receiver 4 according to the embodiment of FIG. 2 will be described in more detail. The FE unit 40 is configured to down-convert a radio frequency (RF) signal transmitted from a unit external to the radio receiver such as the base station 2 (FIG. 1), for example. Further, the FE unit 40 is configured to output a signal having a lower frequency than the RF signal, such as a band signal or an intermediate frequency (IF) signal. The RF signal includes actual data traffic such as control data such as control data transmitted via HS-SCCH of HSDPA and / or data transmitted via HS-PDSCH of HSDPA. The FE unit 40 may be implemented using, for example, a filter and a mixer configured to perform the down-conversion in a well-known manner.

  The VGA 41 has a variable gain. The variable gain is controlled by the AGC unit 45 in order to obtain a relatively stable signal level with respect to the output signal from the VGA 41. The signal level may be an average power level, for example.

  The DC block unit 42 is configured to remove or reduce the DC offset of the output signal from the VGA 41. The DC block unit 42 is further configured to suppress or attenuate unwanted signals that gradually vary at the output of the VGA 41. Such a gradually changing signal may be generated by adjusting the gain of the VGA 41, for example. As described above, the DC block unit 42 may include a filter 42a that removes or reduces the DC offset and / or attenuates the gradual and unwanted signal present in the output signal from the VGA 41. High band (HP) filter or band (BP) filter.

  The ADC 43 is configured to convert the output signal from the DC block unit 42 into a digital output signal, thereby allowing further signal processing using digital signal processing techniques.

  The LP filter 44 is configured to suppress or remove noise and distortion outside the signal band of the digital output signal from the ADC 43.

  The AGC unit 45 is configured to determine, for example, by calculating, estimating or measuring a signal level such as an average power level of the output signal from the LP filter 44. The AGC unit 45 is further configured to control the gain of the VGA 41 based on the signal level, thereby suppressing fluctuations in the signal level of the output signal from the VGA 41.

  The SP unit 46 is configured to determine the quality condition of the communication channel 3. The quality condition is based on the received signal.

  The SP unit 46 is further configured to extract or derive control data such as control data in HS-SCCH of HSDPA based on the output of the LP filter 44. In some embodiments, the SP unit 46 is configured to perform additional signal processing tasks such as channel equalization. The SP unit 46 is configured to forward the output from the LP filter 44, possibly after channel equalization, for further processing. Further processing may include, for example, demodulation and recovery of received data.

  The SP unit 46 is configured to communicate information regarding the quality condition of the communication channel 3 to the CU 47. The CU 47 is configured to determine whether the communication channel 3 facilitates operation in the second mode based on the quality condition.

  According to one embodiment, the quality condition is the SIR of communication channel 3. The SIR may be, for example, the SIR of a received pilot signal.

  In some embodiments, the CU 47 is configured to compare the SIR with a threshold value. The CU 47 is further configured to determine that the communication channel 3 facilitates operation in the second mode if the SIR is above the threshold. The threshold may be different in various embodiments. In some HSDPA embodiments where the data rate easily performed in the second mode rather than the first mode is a data rate of 10 Mbit / s or higher, a threshold of at least 15 dB is appropriate.

  According to another embodiment, the quality condition is a power delay profile (PDP) of communication channel 3. A PDP containing a single dominant peak shows a clear line of sight between, for example, the mobile communication unit 1 and the base station 2 (FIG. 1). However, a PDP with several peaks of equal magnitude indicates that multipath fading exists due to signal reflections to obstacles, for example. The communication channel 3 operates in the second mode when the power ratio between the PDP maximum peak and the second largest peak or one or more other peaks of the PDP, such as all other peaks, exceeds a threshold value. It may be determined to facilitate the process.

  According to yet another embodiment, the quality condition is a combination of SIR and PDP. In the present embodiment, when the SIR exceeds the first threshold and the power ratio between the PDP peaks exceeds the second threshold, it is determined that the communication channel 3 facilitates the operation in the second mode.

  The CU 47 is configured to evaluate at least one configuration condition. The CU 47 configures the wireless receiver 4 to operate in the second mode when all of at least one configuration condition is satisfied, and operates the wireless receiver 4 in the first mode when not satisfied. Further configured to configure. According to an embodiment, one of the at least one configuration condition is that the communication channel 3 is determined to facilitate operation in the second mode.

  According to some embodiments, the CU 47 configures the wireless receiver 4 to operate in the second mode if the communication channel 3 is determined to facilitate operation in the second mode and other The radio receiver 4 is configured to operate in the first mode if it is determined that the communication channel 3 does not facilitate operation in the second mode. In those embodiments, the only configuration condition described above is that the communication channel 3 is determined to facilitate operation in the second mode.

  According to another embodiment, the CU 47 determines that the communication channel 3 facilitates operation in the second mode and places the wireless receiver 4 in the second mode if one or more additional configuration conditions are met. The wireless receiver 4 is configured to operate in the first mode in cases other than the above.

  In one embodiment, the additional configuration condition is that when received data is transmitted via the communication channel 3 at a data rate at which data is easily received in the second mode rather than the first mode. It is to be expected. In this specification, the data rate at which data is easily received in the second mode rather than the first mode is referred to as a high-speed data rate. Similarly, the data rate at which data is easily received in the first mode is called the low data rate. In this embodiment, the SP unit 46 is further configured to communicate control data to the CU 47. The CU 47 is further configured to determine based on the control data whether the received data is expected to be transmitted over the communication channel 3 at a high data rate.

  According to one embodiment, the control unit 47 is configured to configure the radio receiver 4 to operate in the second mode by configuring at least the AGC loop 30 as described below.

  When the AGC unit 45 changes the gain of the VGA 41, a dynamically varying DC level shift occurs at the output of the VGA 41. These dynamically varying DC level shifts may appear as substantially piecewise constant signals that change levels when the AGC unit 45 updates the gain of the VGA 41. Those DC level shifts are suppressed to some extent by the DC block unit 42. However, signal impurities such as spikes or glitches due to DC level shifting are still present at the output of the DC block unit 42. Such signal impurities affect bit errors, and the bit error rate (BER) of the wireless receiver is worsened.

  When the communication channel 3 facilitates the operation in the second mode, the signal level of the input signal to the VGA 41 is relatively stable. When the signal level of the input signal of the VGA 41 is relatively stable, the gain of the VGA 41 does not necessarily need to be adjusted. An example of such a condition is when the average signal power varies at less than 1.5 dB, but is not limited to this. Therefore, the AGC unit 45 may be locked. For example, the output signal from the AGC unit 45 used for controlling the gain of the VGA 41 may be set to a fixed value. By locking the AGC unit 45, the above-described DC level shift is eliminated. Thereby, in this case, signal degradation occurring in the wireless receiver 4 in the VGA 41 is reduced, and the BER of the wireless receiver is improved. Therefore, in one embodiment, the CU 47 is configured to configure the wireless receiver 4 to operate in the second mode by locking the AGC unit 45, thereby facilitating data reception at a high data rate. become.

  In other embodiments, rather than locking the AGC unit 45, the AGC unit 45 is configured to reduce the gain adjustment of the VGA 41 in the second mode compared to operation in the first mode. The Thereby, the signal degradation caused by the DC level shift in the output of the VGA 41 is reduced in the second mode as compared with the first mode. For example, in one embodiment, the update period of the AGC unit 45, i.e., the length of time between when the AGC unit 45 updates the gain of the VGA 41, is increased in the second mode compared to the first mode. This facilitates data reception at a high data rate. According to another embodiment, the AGC unit 45 may be configured to update the gain of the VGA 41 only when the signal level is changed to exceed the threshold in the second mode. For example, the threshold value may be predefined.

  The DC block unit 42 may be a source of so-called inter-chip interference (ICI). For example, in HSDPA, the ICI generated by the DC block unit 42 can affect bit errors and worsen the BER of the wireless receiver. This problem is exacerbated as the data rate increases. When the AGC unit 45 is locked as described above or configured to reduce the gain adjustment of the VGA 41 compared to the first mode, it relates to the suppression of unwanted signals and DC level shifts that vary gradually. The demand on the DC block unit 42 is relaxed.

  Further, when the communication channel 3 facilitates the operation in the second mode, the communication channel 3 does not facilitate the operation in the second mode, or the AGC unit 45 is not locked or the gain of the VGA 41 is increased. Compared to the case where the adjustment is not configured to be reduced, the signal degradation caused by the DC level shift in the output of the VGA 41 is reduced. This is because the signal level of the input signal to the VGA 41 is relatively stable, and therefore, the gain adjustment required to stabilize the signal level of the output signal from the VGA 41 is reduced. Therefore, even if the AGC unit 45 is not locked or configured to reduce the adjustment of the gain of the VGA 41, the demand on the DC block unit 42 regarding suppression of unwanted signals and DC level shifts that are gradually changing will be relaxed. Let's go.

  As described above, when the demand for the DC block unit 42 regarding suppression of unnecessary signals and DC level shift that gradually change is alleviated, the DC block unit 42 passes the output of the VGA 41 directly to the input of the ADC 43, for example. Disabled. Alternatively, the low cutoff frequency of the HP or BP filter 42a of the DC block unit 42 is reduced compared to the low cutoff frequency used when the radio receiver 4 is configured to operate in the first mode. . The ICI generated by the DC block unit 42 is eliminated by disabling the DC block unit 42 or reduced by reducing the low cutoff frequency. Thereby, signal purity improves. As a result, the BER of the radio receiver is also reduced.

  In one embodiment, the CU 47 is configured to configure the wireless receiver 4 to operate in the second mode by disabling the DC block unit 42. This facilitates data reception at a high data rate. Also, the AGC unit 45 may be locked or configured to reduce the adjustment of the gain of the VGA 41 compared to the first mode. Further, the CU 47 is configured to configure the wireless receiver to operate in the first mode by enabling the DC block unit 42.

  In another embodiment, the CU 47 is configured to configure the wireless receiver 4 to operate in the first mode by setting the cutoff frequency of the filter 42a to a first value. Further, the CU 47 is configured to configure the radio receiver 4 to operate in the second mode by setting the cutoff frequency of the filter 42a to a second value smaller than the first value. This facilitates data reception at a high data rate. Further, for operation in the second mode, the AGC unit 45 may be locked or configured to reduce the adjustment of the gain of the VGA 41 compared to the first mode.

  If the communication channel 3 does not facilitate operation in the second mode, the receiver is configured to operate in the second mode by creating the above-described configuration of the AGC unit 45 and / or the DC block unit 42. This can greatly reduce the robustness of the wireless receiver and potentially worsen the BER of the wireless receiver.

  The embodiment shown in FIG. 2 should be considered merely as an example. Some of the units shown in FIG. 2 may be omitted in some embodiments, and other additional units may be included. Further, in some embodiments, the units of the wireless receiver 4 may be configured and connected in ways other than that shown in FIG. For example, according to one embodiment, the entire AGC loop 30 is analog. Further, the ADC 43 and the digital LP filter 44 are omitted in the AGC loop 30, and the output from the DC block unit 42 is directly supplied to the AGC unit 45. In the present embodiment, the AGC unit 45 operates on an analog input signal. The AGC loop 30 may further comprise a level shifting network (not shown) for ensuring an appropriate operating point within the AGC loop 30, for example. Further, in the present embodiment, the output of the DC block unit 42 is supplied to the input of the SP unit 46. The SP unit 46 may comprise an ADC (not shown) for converting the output from the DC block unit 42 into a digital signal, thereby enabling the use of digital signal processing techniques within the SP unit 46.

  FIG. 3 a is a block diagram illustrating one embodiment of the DC block unit 42. When the wireless receiver 4 is configured to operate in the first mode and the second mode, respectively, the DC block unit 42 is configured to be enabled and disabled by the CU 47. For operation in the first mode, the input signal to the DC block unit 42 is directed to the filter 42a via the switch 60 controlled from the CU 47. For operation in the second mode, the switch 60 is set by the CU 47 to avoid the filter 42a, so that the input signal to the DC block unit 42 is directly transferred as the output signal of the DC block unit 42. The DC block unit 42 is disabled.

  FIG. 3 b shows another embodiment of the DC block unit 42. In this embodiment, the filter 42a has a controllable low cutoff frequency, which may be controlled from the CU 47. The filter 42 a includes a first sub filter 61 and a second sub filter 62. The low cutoff frequency of the first sub-filter 61 has the first value. The low cutoff frequency of the second sub-filter 62 has the second value. An input signal to the DC block unit 42 is supplied as an input signal to both the first sub-filter 61 and the second sub-filter 62. The switch 63 controlled by the CU 47 selects an output signal from the first sub-filter 61 or the second sub-filter 62 and transfers the selected output signal as an output signal of the DC block unit 42. For operation in the first mode, the switch 63 is set to select the output signal from the first sub-filter 61. For operation in the second mode, the switch 63 is set to select the output signal from the second sub-filter 62. According to other embodiments, more than two sub-filters may be employed to obtain additional degrees of freedom when setting the cutoff frequency of the filter 42a.

  According to some embodiments, the filter 42a is implemented using active elements such as operational amplifiers and / or transconductors in combination with passive elements such as resistors and / or capacitors. For example, the filter 42a may be realized as an active RC filter or a GmC filter. Methods for adjusting or adjusting the frequency response of such filter implementations by changing the capacitance value for the filter capacitor are well known. FIG. 3 c shows an embodiment of the DC block unit 42. In FIG. 3c, the filter 42a comprises a block of filter elements 64, for example active and passive elements, and a capacitor bank 65. Capacitor bank 65 comprises a plurality of switchable capacitors that may be individually connected to or disconnected from the internal node of filter 42a to change the capacitance value and thus the cutoff frequency of filter 42a. This may be performed, for example, according to well-known filter adjustment techniques. In the embodiment of FIG. 3c, the cutoff frequency of the capacitor bank 65 and thus the filter 42a is controlled from the CU 47.

  FIG. 4 is a flowchart illustrating an embodiment of a method for operating the wireless receiver 4. The quality condition of the communication channel 3 is determined in step 110. In step 120, it is determined whether the communication channel 3 facilitates operation in the second mode. The wireless receiver 4 is configured to operate in the first mode or the second mode in step 130.

  According to one embodiment, the quality condition is the SIR of the communication channel 3, such as the SIR of the pilot signal. Determining the quality condition in step 110 includes determining the SIR, for example by measuring or estimating. Further, determining whether the communication channel 3 facilitates operation in the second mode in step 120 includes comparing the SIR to a threshold value. For example, in step 120, it may be determined that the communication channel 3 facilitates operation in the second mode when the SIR exceeds a threshold.

  In step 130, the wireless receiver 4 is configured to operate in the second mode if all of the at least one configuration condition is satisfied, and to operate in the first mode if not satisfied. According to an embodiment, one configuration condition is that the communication channel 3 is determined to facilitate operation in the second mode.

  According to some embodiments of the method, in step 130, based on quality conditions only, the wireless receiver 4 is configured to operate in the second mode. For example, the wireless receiver operates in the second mode when it is determined that the communication channel 3 facilitates the operation in the second mode based on the quality condition, and operates in the first mode otherwise. It may be configured to. This is shown in the flowchart of FIG. FIG. 5 illustrates one embodiment of step 130 (FIG. 4). It is investigated in step 131a whether it is determined in step 120 (FIG. 4) that the communication channel 3 facilitates operation in the second mode. If the answer to step 131a is yes, then in step 132a, the wireless receiver is configured to operate in the second mode. If the answer to step 131a is no, then in step 133a, the wireless receiver is configured to operate in the first mode. In the case of the embodiment of FIG. 5, the only configuration condition described above, that is, it is determined that the communication channel 3 facilitates operation in the second mode.

  According to another embodiment, if it is determined that communication channel 3 facilitates operation in the second mode and at least one additional configuration condition is met, in step 130 (FIG. 4), the wireless receiver It is configured to operate in two modes. An example of such an embodiment is shown in the flowchart of FIG. FIG. 6 shows another embodiment of step 130 (FIG. 4). Whether it is determined in step 120 (FIG. 4) that communication channel 3 facilitates operation in the second mode is investigated in step 131b. If the answer in step 131b is no, in step 133b, the wireless receiver 4 is configured to operate in the first mode. If the answer in step 131b is yes, in step 134, control data indicating the data rate of the received data is extracted. The control data extracted in step 134 may be control data received via the communication channel 3. In one embodiment of HSDPA, the control data is received via HS-SCCH. In step 135, it is determined whether the control data extracted in step 134 indicates that the received data is expected to be transmitted over the communication channel 3 at a high data rate. That is, in this embodiment, one configuration condition is that the received data is expected to be transmitted via the communication channel 3 at a high data rate. If the answer in step 135 is yes, in step 132b, the wireless receiver is configured to operate in the second mode. If the answer to step 135 is no, then in step 133b, the wireless receiver is configured to operate in the first mode.

  Compared to the embodiment of FIG. 5, the advantage of the embodiment of FIG. 6 is that an unnecessary configuration to the second mode may be avoided. For example, if only a low data rate is used, the second mode is not required, and if the channel conditions fluctuate at the boundary between conditions that facilitate operation in the second mode and conditions that do not facilitate, wireless It may be beneficial to the robustness of the receiver to operate the receiver 4 in the first mode to avoid frequent switching between the first mode and the second mode.

  According to some embodiments, the control data based upon the determination at step 135 includes information that explicitly indicates the data rate used for the received data. Step 134 may include extracting the explicit information from the control data.

  In HSDPA, information that explicitly indicates a data rate used for data transmitted via HS-PDSCH is included in control data transmitted via HS-SCCH. However, the mutual timing of the HS-PDSCH and the HS-SCCH is such that the reception of data on the HS-PDSCH to which the explicit information of the data rate is related before the wireless receiver 4 receives the explicit information. It is time to start. Therefore, in HSDPA, since the configuration of the radio receiver needs to be performed before data is received via HS-PDSCH, the explicit information of the data rate transmitted via HS-SCCH is: It is not used as a basis for the determination of step 135. However, before the data is transmitted via the HS-PDSCH, other information is transmitted via the HS-SCCH. Such other information indicates whether the received data is likely to be transmitted at a high data rate. Accordingly, other information may be used as a basis for the determination of step 135. Examples of other information are the number of spreading codes or data packet channelization codes and the modulation scheme. In HSDPA, 1-15 data packet channelization codes may be used. A higher number of data packet channelization codes indicates a faster data rate. Furthermore, the modulation scheme used in HSDPA is four-phase phase modulation (QPSK) or 16-value quadrature amplitude modulation (16-QAM).

  According to one embodiment, step 135 includes extracting the number of data packet channelization codes from the control data. If the number of data packet channelization codes is greater than or equal to a threshold, the received data is expected to be transmitted over the communication channel 3 at a high data rate. According to one embodiment of HSDPA, the threshold is 15 (ie, the maximum number of codes). According to another embodiment of HSDPA, the threshold is 11, which is the minimum number of data packet channelization codes required to allow a data rate of 10 Mbit / s. The theoretical maximum value of the data rate for each HSDPA data packet channelization code is 0.93 Mbit / s. Of course, the appropriate threshold may vary between various applications and receiver implementations. Thus, the given examples should not be considered limiting.

  According to another embodiment, step 134 includes extracting a modulation scheme from the control data. If a specific modulation scheme is used, the received data is expected to be transmitted over the communication channel 3 at a high data rate. The particular modulation scheme may be different in various applications. According to one embodiment of HSDPA, the specific modulation scheme is 16-QAM.

  The determination of step 135 may be based on a combination of the number of data packet channelization codes and a modulation scheme. According to some embodiments of HSDPA, if at least Nth data packet channelization codes are used with modulation scheme 16-QAM, the received data is expected to be transmitted at a high data rate in step 135. It is determined. Nth is a threshold level. According to one particular embodiment, Nth is 15. Fifteen data packet channelization codes along with the modulation scheme 16-QAM are used at high data rates (14 Mbit / s) in HSDPA. According to other embodiments of HSDPA, Nth is 11, 12, 13 or 14. Of course, the appropriate value of Nth may vary between various applications and receiver implementations. Thus, the given examples should not be considered limiting.

  According to one embodiment, the control data includes a coding rate for the received data. Step 134 may include extracting an encoding rate from the control data.

  According to some embodiments, step 132a (FIG. 5) and step 132b (FIG. 6) include locking the AGC unit 45 (FIG. 2) of the wireless receiver 4. Alternatively, step 132a (FIG. 5) and step 132b (FIG. 6) may configure the AGC unit 45 to reduce the gain adjustment of the VGA 41 (FIG. 2) as compared to operation in the first mode. May be included. For example, the update period of the AGC unit 45 may be increased compared to operation in the first mode, or the AGC unit 45 may be changed so that the signal level exceeds a threshold that may be predefined, for example. The gain of the VGA 41 may be updated only when

  Further, step 132a (FIG. 5) and step 132b (FIG. 6) may alternatively or additionally disable the DC block unit 42 (FIG. 2) or set the cutoff frequency of the filter 42a to a second value. May be included. Similarly, step 133a (FIG. 5) and step 133b (FIG. 6) may include enabling the DC block unit 42 or setting the cutoff frequency of the filter 42a to a first value.

  The methods described above using the various embodiments may be performed for each packet of data received, eg, in a packet data communication environment. Alternatively, the method may be performed regularly or irregularly, such as every two, three, or every four packets of data.

  In conventional solutions for dealing with maximum data rates in HSDPA etc., the radio typically includes relatively stringent circuit requirements such as noise figure, frequency and timing drift, phase noise, image rejection and providing a DC offset to the received signal. Design is adopted. Such requirements can be more stringent than necessary for low data rates, for example in HSDPA, which is typically used more frequently than the maximum data rate. A network in an AGC loop or the like designed for operation under a wide variety of channel conditions to facilitate reception of all available data rates in HSDPA when operating at the low data rate. Furthermore, it occupies a larger chip area than necessary and consumes a larger amount of power than necessary.

  In the embodiments described herein, the wireless receiver 4 is configured to operate in the second mode under appropriate channel conditions, i.e., channel conditions that facilitate operation in the second mode. . The wireless receiver 4 is a component of the wireless receiver 4 that is used under low-quality channel conditions, such as channel conditions that do not facilitate operation in the second mode, to compensate for signal degradation that occurs in the channel. Is configured to operate in the second mode by disabling and / or adapting. With this configuration, as described above, the wireless receiver 4 does not adopt a wireless design including relatively strict requirements required in other configurations, and the maximum data rate in HSDPA (a data rate of 10 Mbit / s or more). Etc.) can handle these maximum data rates under channel conditions that allow the use of This reduces the complexity of the wireless receiver in that, for example, a relatively low cost wireless receiver network is obtained with respect to circuit area and power consumption. This is one advantage.

  The wireless receiver 4 may be included in a communication unit, for example. The communication unit may be, for example, the mobile communication unit 1 (FIG. 1), a portable or handheld mobile radio communication unit, a mobile radio terminal, a mobile phone, a communication device, an electronic organizer, or a smartphone, but is not limited thereto.

  The present invention may be incorporated into a computer program product to enable the implementation of the methods and functions described herein. The present invention may be executed when a computer program product is loaded and executed on a system having computer functions. A computer program, software program, program product, or software in this specification is an instruction intended to cause a system having a processing function to directly execute a specific function or to be executed after conversion into another language, code, or notation. Means any expression that expresses the set in any programming language, code or notation.

  The present invention has been described above with reference to specific embodiments. However, embodiments other than those described above are possible within the scope of the invention. Method steps other than those described above for performing the method by hardware or software may be provided within the scope of the present invention. Different features and steps of the invention may be combined in combinations other than those described above. The scope of the invention is limited only by the appended claims.

Claims (27)

A method of operating a wireless receiver (4) configured to receive data via a communication channel (3) in a first mode or a second mode, comprising:
The second mode facilitates receiving data at a faster data rate than the first mode;
Determining a quality condition of the communication channel (3);
Determining whether the communication channel (3) facilitates operation in the second mode based on the quality condition;
Evaluating at least one configuration condition, one of which is determined that the communication channel (3) facilitates operation in the second mode;
-Operating in the second mode when all of the at least one configuration condition is satisfied;
-Configuring the radio receiver (4) to operate in the first mode otherwise;
Have
The step of configuring the radio receiver (4) to operate in the second mode includes locking an automatic gain control unit (45) of an automatic gain control loop (30) of the radio receiver. A method characterized by that. Configuring the radio receiver (4) to operate in the first mode comprises enabling a DC block unit (42) of the automatic gain control loop (30);
The The method of claim 1, wherein further comprising the step of disabling the DC-block unit (42) constituting the radio receiver (4) to operate in said second mode. The step of configuring the radio receiver (4) to operate in the first mode comprises setting a cutoff frequency of the filter (42a) of the DC block unit (42) of the automatic gain control loop (30) to a first value. Including the step of setting to the value of
The step of configuring the wireless receiver (4) to operate in the second mode comprises setting a cutoff frequency of the filter (42a) to a second value;
The method of claim 1, wherein said first value, characterized in that greater than said second value. The method according to any one of claims 1 to 3 , characterized in that the quality condition is a signal to interference ratio of the communication channel (3). The step of determining whether the communication channel (3) facilitates operation in the second mode comprises:
Determining that the communication channel (3) facilitates operation in the second mode if the signal to interference ratio exceeds a threshold;
-Otherwise, determining that the communication channel (3) does not facilitate operation in the second mode;
The method of claim 4 comprising: Whether the received data is expected to be transmitted over the communication channel (3) at any data rate at which data is easily received in the second mode rather than the first mode. Further comprising determining based on control data received via the communication channel (3),
One of the at least one configuration condition is that the received data is received at the communication channel (3) at the arbitrary data rate at which data is easily received in the second mode instead of the first mode. 6) The method according to any one of claims 1 to 5 , characterized in that it is expected to be transmitted via a). It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. The step of determining whether
Deriving from the control data the number of data packet channelization codes used for the received data;
It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. Determining based on the number of data packet channelization codes;
The method of claim 6 comprising: It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. The step of determining whether
Deriving a modulation scheme to be used for the received data from the control data;
Whether the received data is expected to be transmitted over the communication channel at the arbitrary data rate at which data reception is facilitated in the second mode rather than the first mode. The method according to claim 6 or 7 , further comprising the step of determining based on a modulation scheme. It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. The step of determining whether
Deriving from the control data the coding rate used for the received data;
It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. Determining based on the encoding speed;
The method according to any one of claims 6 to 8 , characterized by comprising: The method according to any one of claims 1 to 8 , characterized in that the communication channel (3) is a high speed downlink packet access communication channel. The method according to any one of claims 1 to 9 , characterized in that the communication channel (3) is an orthogonal frequency division multiplexing communication channel. Computer program comprising the computer program code for performing the method according to any one of claims 1 to 11 , when the computer program code is executed by an electronic device having a computer function. A computer readable medium storing a computer program comprising the computer program code for performing the method according to any one of claims 1 to 11 , when the computer program code is executed by an electronic device having a computer function. A wireless receiver (4) configured to receive data via a communication channel (3) in a first mode or a second mode,
Making it easier for the second mode to receive data at a faster data rate than the first mode;
A signal processing unit (46) configured to determine a quality condition of the communication channel (3);
An automatic gain control loop (30) comprising a variable gain amplifier (41) and an automatic gain control unit (45) configured to control the gain of the variable gain amplifier (41);
A control unit (47),
It is determined based on the quality condition whether the communication channel (3) facilitates operation in the second mode, and at least one configuration condition, one of which is the communication channel (3) Evaluating the configuration conditions, which are to be determined to facilitate the operation in the second mode,
-Operating in the second mode when all of the at least one configuration condition is satisfied;
-Configured to configure the wireless receiver (4) to operate in the first mode otherwise;
A control unit (47);
Comprising
The radio receiver (4), wherein the control unit (47) is configured to lock the automatic gain control unit (45) in the second mode. Radio receiver (4) according to claim 14 , characterized in that said automatic gain control loop (30) comprises a DC block unit (42). The control unit (47) is configured to enable the DC block unit (42) in the first mode and to disable the DC block unit (42) in the second mode. A wireless receiver (4) according to claim 15, wherein The DC block unit (42) includes a filter (42a),
The control unit (47) is configured to set the cutoff frequency of the filter (42a) to a first value in the first mode and to a second value in the second mode,
16. The radio receiver (4) according to claim 15, wherein the first value is greater than the second value. Radio receiver (4) according to any one of claims 14 to 17 , characterized in that the quality condition is a signal to interference ratio of the communication channel (3). The control unit (47) is configured to determine that the communication channel (3) facilitates operation in the second mode when the signal to interference ratio exceeds a threshold. Radio receiver (4) according to claim 18 . The signal processing unit (46) is further configured to extract control data from the received signal;
The control unit (47) transmits the received data via the communication channel (3) at an arbitrary data rate at which data is easily received in the second mode rather than the first mode. Further configured to determine whether to be expected based on the control data;
One of the at least one configuration condition is that the received data is received at the communication channel (3) at the arbitrary data rate at which data is easily received in the second mode instead of the first mode. ) Radio receiver (4) according to any one of claims 14 to 19 , characterized in that it is expected to be transmitted via a). The control unit (47)
Deriving from the control data the number of data packet channelization codes used for the received data;
It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. 21. The wireless receiver (4) of claim 20 , further configured to determine whether based on the number of data packet channelization codes. The control unit (47)
Deriving from the control data the modulation scheme used for the received data;
It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. 22. The radio receiver (4) according to claim 20 or 21 , further configured to determine whether or not based on the modulation scheme. The control unit (47)
Deriving from the control data the coding rate used for the received data;
It is expected that the received data will be transmitted via the communication channel (3) at the arbitrary data rate where data reception is easily performed in the second mode rather than the first mode. 23. The radio receiver (4) according to any one of claims 20 to 22 , further configured to determine whether or not based on the encoding rate. 23. Radio receiver (4) according to any one of claims 14 to 22 , characterized in that the communication channel (3) is a high speed downlink packet access communication channel. 24. Radio receiver (4) according to any one of claims 14 to 23 , characterized in that the communication channel (3) is an orthogonal frequency division multiplex communication channel. Communication unit (1) comprising a radio receiver (4) according to any one of claims 14 to 25 . The communication unit is any one of a portable or handheld mobile radio communication unit, a mobile radio terminal, a mobile phone, a pager, a communication device, an electronic organizer, and a smartphone. 26. Communication unit (1) according to 26 .

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