TWI511471B - Receiver and method for the reception of a node by a receiver in a wireless network - Google Patents

Description

Method for receiving a node by using a receiver in a receiver and a wireless network

The present invention relates to a receiver and a method of receiving a node using a receiver in a wireless network.

The industry standard IEEE 802.15.4 sets forth a specification for a low rate WPAN (Wireless Personal Area Network). A wireless network typically has a plurality of nodes each having a transceiver device for the nodes to communicate with each other. Each transceiver device has a transmitter and a receiver.

A transmitter of a transmitting node of a wireless network converts a stream of data to be transmitted into a radio signal to be transmitted via an antenna in accordance with the IEEE 802.15.4 industry standard. The data stream to be transmitted is first converted into so-called symbols, wherein each symbol is assigned a value having a fixed bit width (e.g., four bits). The symbols are converted into a specific sequence of contiguous symbol values (specifically a PN sequence) having a number of binary chips. In this context, each symbol is assigned exactly one sequence. For example, a symbol is defined by a sequence having one of a sequence of 32 chips.

For example, a 4-bit wide transmission is defined by 16 different symbols, with 16 different PN sequences being provided accordingly. In this context, the length of time of a symbol corresponds to the duration of transmission of all chips of the assigned PN sequence, wherein in each case the first and last chips of the PN sequence are adjacent to the front of the symbol and / or rear restrictions.

The connected PN sequence is then modulated by the transmitter, spectrally shifted into one of the communication channels, and finally amplified for transmission.

The transmitted radio signal is received by a receiver of one of the receiving nodes by means of an antenna. The receiver converts the received signal from the radio signal into the data as error-free as possible according to the specifications of the IEEE 802.15.4 industry standard, wherein the received signal can be filtered by the receiver, converted to baseband, and demodulated. And detect the data. If the band extension on the transmitting side occurs with the aid of a sequence on the transmitting side, the band spreading is cancelled on the receiver side by using despreading corresponding to one of the sequences on the receiver side. Each sequence on the receiver side is assigned to a sequence on the transmitter side that can be derived or even equivalent thereto. For example, the received signal is correlated by means of a correlator using a known PN sequence on the receiver side. If the chip of the sequence on the transmitter side selects two logical values 0 and 1 or two of its equivalent mapping values ±1, then the chip is usually also used in the receiver to select a completely different value (for example, 0). And a sequence of 1 or ±1).

The industry standard IEEE 802.15.4-2006, pages 21, 43 discloses a frame structure for transmission that conforms to the standard. The frame has an SHR (Synchronization Header), and the SHR has a preamble and has an SFD (Frame Start Delimiter) frame alignment word and a data field.

The SHR allows the receiver to synchronize itself to receive subsequent data. The receiver uses the preamble to perform at least one chip sync and one symbol sync on the incoming received signal. The synchronization performed creates one of the synchronization conditions of the receiver, wherein the receiver can receive subsequent data by means of the time base. The data field in the received signal follows the SFD frame alignment word, and the time base can be used to demodulate and detect the data of the data field.

To detect the symbols contained in the received signal and/or to determine the symbol side The SHR sync header preamble format contains a known sequence on the receiving side (eg, a PN sequence). Based on the preamble, a time base having a sampling instant of the chip and having a symbol boundary is determined in the receiver.

For synchronization on the receiver side, the received signal may first be supplied to a cross-correlation filter, for example, which performs a cross-correlation between the received signal and the preamble. The output signal of the cross-correlation filter has a periodic maximum indicating a correlation maximum value in each case. A cross-correlation maximum is formed in the case where the preamble contained in the received signal is completely or nearly completely overlapped with the preamble preamble on the receiving side. Thus, for example, based on the correlation maximums detectable by, for example, a threshold detector, conclusions can be drawn regarding the boundaries of the respective symbols.

Accordingly, the object of the present invention is to indicate a method for receiving a node in a wireless network to permit a robust reception as much as possible.

This goal is solved by a method having one of the features of claim 1. The preferred development form is the subject matter of the appended claims and can be found in the description.

Accordingly, a method for receiving a node using a receiver in a wireless network is provided. The wireless network has two nodes, for example, a node for transmitting radio signals and a node for receiving radio signals. The method is for receiving by a receiver receiving the node, wherein one of the received signals is formed by a radio signal received via an antenna.

A first time base is determined by means of synchronization. The synchronization can include multiple parts. With this synchronization, suitable sampling moments for chip and/or symbol boundaries and/or a time offset and/or a frequency offset are determined for the first time base. The first time base thus forms a time reference for detecting data following the preamble.

Preferably, oversampling of the received chips of the received signal is performed. A suitable sampling instant for the chips is located by correlating one of the preambles included in the portion of the received signal with a known preamble on the receiver side by means of a synchronous correlator. For this purpose, the synchronization correlator is assigned to the preamble. Synchronization is performed using the associated maximum value.

The symbol boundary of the received symbol of the frame is determined by the associated maximum value and the oversampling. Additionally, in particular, a synchronization is performed within the frame by means of an SFD frame alignment word, wherein for this purpose the SFD frame alignment word has a clearly defined position within the frame.

Using the first time base of the synchronization decision enables the receiver to determine the data following the frame alignment word of the frame.

In a first aspect of the invention, a first energy value of one of the received signals is determined during reception by the receiver. In addition, during reception of the frame, one of the second energy values of the received signal is continuously determined. The first energy value and the second energy value are respectively assigned to one of the signal strengths of the radio signal. The second energy value is determined after the first energy value in time, ie, separated from the first energy value in time. The first energy value and the second energy value are preferably stored in a memory for further evaluation.

A difference is determined based on a difference between the second energy value and the first energy value. The difference is compared to a threshold. For example, the threshold A time-constant threshold or a temporally variable value for comparison with the difference. The threshold in the receiver is preferably predetermined and at least temporarily stored. Another option is to use the previous time energy value to determine the threshold. For example, to compare the difference to the threshold, a larger/smaller comparison can be performed.

In a second aspect of the invention, one of the quality values of the received signal is continuously determined during reception of the frame. This quality value is measured in one of the communication channels for interference (eg, signal distortion). For example, signal distortion can be caused by interference and/or multipath propagation. Minor interference produces a large quality value, and vice versa. This quality value is less dependent on the energy value than the previously mentioned interference in the communication channel. For example, the quality value is generated by comparing the received signal with one of the expected signal forms on the receiver side (which may be in the form of a correlation decision).

In particular, the quality value is a value of one of the signal ratios or one of the values of the correlator output signal of one of the correlators. In this context, the correlator on the receiver side correlates the known PN sequence with the chip assigned to the symbol of the received signal to determine the transmitted data.

Compare the quality value to a quality threshold. For example, the quality threshold is a temporally constant quality threshold or a temporally variable value compared to the quality value. This quality threshold is preferably determined by the receiver and temporarily stored. For example, a (limited) previous time quality value can be used to determine the quality threshold. For example, to compare the quality value to the quality threshold, a larger/smaller comparison can be performed.

During the reception of the frame, according to the first aspect, the threshold value is exceeded. In the case of and/or in the case where the sample quality of the second state falls below the quality threshold, the first time base is erased and the synchronization for determining the update of a second time base is started. In this context, the receipt of the frame is aborted before the frame is completed.

A comparison between the first aspect difference and the threshold value and a comparison of the second state sample quality value to the quality threshold value may alternatively be used or combined. For the purpose of combination, it is preferred to logically link the result of the comparison of the difference to the threshold and the result of the comparison of the quality value to the quality threshold. For example, the results may be arranged for an OR operation such that the first execution may be performed if the difference exceeds the threshold or if the quality value falls below the quality threshold Time base erasure and synchronization of an update. Embodiments using a combination evaluation have the advantage that in the event of an energy jump with a very small energy value, an evaluation can be performed due to the ongoing noise and the deficiencies associated therewith. The energy value may exceed the threshold due to stray radiation from a source such as a microwave, for example, where the correlation may be very small, such that the quality value may fall below the quality threshold. In such cases, the reception of the current frame is aborted.

For example, a significant improvement in receiving a frame in a wireless network is achieved using one of the techniques discussed previously (eg, discussed in more detail in conjunction with the figures), wherein interference is also present therein and/or severe A more robust launch in one of the wireless networks used. In a heavily occupied wireless network with heavy interference, it can occur that a frame with higher energy or a heavier interference during reception of the current frame can decode the frame without error. The extent of the data affects the frame that is currently being received. here In this case, the continued reception of the current frame is useless and the receiving process is aborted. However, frames with higher energy can be received.

Furthermore, the object of the present invention is to indicate a receiver that is one of the nodes of a wireless network that is as improved as possible.

This target is solved by a receiver having the characteristics of independent request item 7. A preferred form of development can be found in the description.

Accordingly, a receiver for receiving one of the nodes of the wireless network for receiving a received signal is provided. The node may additionally have a transmitter and a data processor, such as a microcontroller. In this context, the invention relates to a receiver for a node. The receiver has at least one digit circuit, a synchronization unit and an evaluation device. Additionally, the receiver can have other components for receiving the received signals, such as amplifiers, filters, mixers, analog/digital converters, and the like.

The digital circuit is configured to detect received data of a frame of the received signal. For this purpose, the digital circuit has, in particular, a correlator on the receiver side for cross-correlation of known sequences of chips in the received signal.

The synchronization unit is configured to determine the first time base by synchronization. For this purpose, the synchronization unit has in particular a synchronization correlator for cross-correlating the preamble in the received signal with the known preamble on the receiver side.

The digital circuit is configured to detect the received data of the frame by using the first time base.

The evaluation device is configured to control the digital circuit and the synchronization unit. For this purpose, preferably the control output of the evaluation device and the digit At least one control input of the circuit and at least one control input connection of the synchronization unit.

In a first aspect, the evaluation device is configured to determine a first energy value of the received signal during the receiving of the frame, continuously determine a second energy value of the received signal, to identify A difference from the difference between the second energy value and the first energy value is compared to a threshold value. The evaluation circuit is configured to erase the first time base and control the determination of a second database if the difference exceeds the threshold.

In a second aspect, the evaluation device is configured to continuously determine a quality value of the received signal during the receiving of the frame and compare the quality value to a quality threshold. The evaluation circuit is configured to erase the first time base and control the determination of a second database if the quality value falls below the quality threshold.

The first aspect and the second aspect can be individually applied for this purpose. It is also possible to combine the settings of one of the evaluation devices, wherein the difference is compared to the threshold and the quality value and the quality threshold.

The embodiments described subsequently refer to the method for receiving and to the receiver.

In a preferred embodiment, a signal field strength value (RSSI) is formed. The first energy value and the second energy value are determined by averaging a number of values (RSSI) of the signal field strength of the radio signal. For example, the first energy value is determined by averaging four connected values (RSSI) of the signal field strength.

Preferably, the second is determined at a constant time interval from the first energy value Energy value. In a preferred embodiment, the first energy value and the second energy value are continuously determined in a shift time window. The boundary of the time window is preferably defined by a fixed number of energy values within the time window.

According to a preferred development of the invention, at least two differences are determined for at least two first energy values. For this purpose, the first two energy values are assigned to different times. For example, the two first energy values are continuous. Each of the at least two differences is compared to the threshold. The logic is used to evaluate the result of the comparison of at least two differences. Preferably, the result of the comparison is logically linked for an OR operation.

In a preferred embodiment, the quality measurement is used to determine the quality value and quality threshold. It is advantageous to use one of the correlators to output a signal to determine the quality measurement. For example, a quality measurement is determined for exactly one symbol that is transmitted.

For example, the quality measurement is the maximum of one of the output signals of the correlator.

According to a preferred embodiment, a plurality of quality measurements are continuously determined in a shift time window. Preferably, the boundary of the time window is defined by a fixed number of quality measurements within the time window.

Other development form variations previously described are particularly advantageous, individually and in combination with each other. In this context, all other development form variations can be combined with one another. Some possible combinations are explained in the description of the illustrated embodiments in the various figures. However, the possibility of a combination of other forms of development represented is never decisive.

The following embodiments are discussed with reference to the IEEE 802.15.4 industry standard, but they can also be used correspondingly for other wireless networks with multiple nodes. For this purpose, each node should have a transmitter/receiver device with a transmitter and a receiver, respectively. The invention discussed hereinafter with the embodiments refers to a receiver of a node and a method for receiving by a receiver of a node.

The receiver converts the received signal formed by the radio signal into the transmitted data according to the specifications of the IEEE 802.15.4 industry standard, wherein the received signal is filtered by the receiver, transformed into a baseband, demodulated, and solved. Expand and detect the data. In order to convert the received signal into (initially transmitted) data, the receiver requires a time base, for example, the time base includes a chip and/or symbol boundary and/or a time offset and/or a frequency offset. Move to fit the sampling moment.

FIG. 1 schematically illustrates a first time base sync1 and a second time base sync2 as a block in the illustration. To determine the first time base sync1 and the second time base sync2, a synchronization is performed. For example, for synchronization on the receiver side, one of the cross-correlation between the received signal and the known preamble on the receiver side is first performed. The cross-correlated output signal has a periodic maximum indicating the associated maximum value for each case. A cross-correlation maximum is formed in the case where the preamble contained in the received signal is completely or nearly completely overlapped with the known preamble for cross-correlation on the receiving side. For this reason, based on the correlation maximum, a conclusion can be drawn about the symbol boundary of the first time base sync1 and/or the second time base sync2 and the sampling time of the chip.

Figure 1 illustrates a schematic diagram of one of the time domains with time t ₁ to t ₁₀ of time t. The time bases sync1 and sync2 are represented in the bottom area. Above the time bases sync1 and sync2, the symbols Sym1, Sym2, Sym3, Sym1', Sym2' are schematically represented as a number of squares in their chronological order. Symbol boundaries are represented by lines. Eight RSSI values (received signal strength indications) are output for each symbol Sym1, Sym2, and the like. The four RSSI values are each averaged to yield an energy value E _t1 , E _t2 , E _t3 , E _t4 , E _t5 .

In the central region of the schematic diagram in Fig. 1, with time t (as an example, at times t ₁ , t ₂ , t ₃ , t ₄ , t ₅ , t ₆ , t ₇ , t ₈ , t ₉ , t ₁₀ ) indicates the behavior of the energy value S(t). The behavior of the RSSI value is also expressed as a dashed line.

The data of a frame is received at times t ₁ , t ₂ and t ₃ . The associated energy values E _t1 , E _t2 , E _t3 are correspondingly low due to the low signal field strength of the received radio signal. During the second half of the second symbol Sym2, the signal field strength in the received channel and thus the RSSI value increases significantly. In the embodiment of Figure 1, the increase in signal field strength is dependent on the start of transmission by another node in the wireless network of the receiving node. As the energy in the transmission channel increases, the energy values E(t) having the values E _t4 and E _t5 rise sharply at times t ₄ and t ₅ . Thereafter, the energy value E(t) is also maintained at a higher level during the following additional times t ₆ , t ₇ , t ₈ , t ₉ and t ₁₀ .

In the upper region of the diagram, the behavior of the two differences ΔE1(t), ΔE2(t) is indicated with respect to time t. The determination of the differences ΔE1(t), ΔE2(t) is discussed in the following embodiment variations. Again, a constant threshold S during the transmission is schematically indicated.

In a variation of the first embodiment of FIG. 1, the reception of the frame FRX A first energy value E(t-1) of one of the received signals and a second energy value E(t) of the received signal are determined during the period. In this first embodiment variant, the second energy value E(t) is determined at an actual time t. However, in this first embodiment variant, the first energy value E(t-1) is determined at a previous time t-1. Therefore, the second energy value E(t) is determined after the first energy value E(t-1) in time.

In this first embodiment variant, the following formula applies: ΔE1(t)=E(t)-E(t-1) (1)

In this context, ΔE1(t) determines a difference based on the difference between the second energy value E(t) and the first energy value E(t-1). The difference ΔE1(t) is temporally determined immediately after the second energy value E(t) and is assigned to the time t of the second energy value E(t).

For example, for the difference ΔE1 _t s of the time TS in Fig. 1, the following formula is applicable: ΔE1 _t5 = E _t5 -E _t4 (2)

In this context, t _{5 is the time} at which the second energy value E _t5 and the difference ΔE1 _t5 are assigned, and t ₄ is the time at which the first energy value E _t4 is assigned.

In a variant of the second embodiment of FIG. 1, a first energy value E(t-2) of the received signal and a second energy value E(t) of the received signal are also determined during reception of the frame FRX. ). In a second embodiment variant, the second energy value E(t) is also assigned to the last time decision of the current time t. On the other hand, in this second embodiment variant, the first energy value E(t-2) is determined for one of the times t-2 before the current time t. Therefore, in a second embodiment variant, another determination for time t-1 is at the first energy The occurrence of the value E(t-2) and the determination of the second energy value E(t) occurs, however, this consideration is not used for subtraction.

In this second embodiment variant, the following formula applies: ΔE2(t)=E(t)-E(t-2) (3)

In this context, ΔE2(t) determines a difference based on the difference between the second energy value E(t) and the first energy value E(t-2). The difference ΔE2(t) is the time t assigned to the second energy value E(t).

For example, for the difference ΔE2 _{t5 in} FIG. 1 for time t ₅ , the following formula is applicable: ΔE2 _t5 =E _t5 -E _t3 (4)

In this context, t _{5 is the time} at which the second energy value E _t5 and the difference ΔE2 _t5 are assigned, and t ₃ is the time at which the first energy value E _t3 is assigned.

Figure 1 shows that the difference ΔE2 _t5 of the variant of the second embodiment exceeds the threshold S at time t ₅ . On the other hand, the difference ΔE1 _t5 of the variation of the first embodiment does not exceed the threshold value S at time t ₅ . Two embodiment variations can be combined with each other. The combination evaluation of one of the difference ΔE1(t) of the variation of the first embodiment and the difference ΔE2(t) of the variation of the second embodiment is preferably performed by means of a logic. For example, the comparison result of each comparison of the respective difference values ΔE1(t) and ΔE2(t) is linked with the threshold value S to perform an OR operation.

Alternatively lines, may be provided to, a first energy value E ₀ is determined at the start of emission of the information frame FRX (not shown) and stored energy in a first frame duration information FRX the value E _0, since in order to achieve the respective the current value of the second energy E (t) by subtracting the first constant energy of the inquiry in block ₀ of the subtraction value E FRX. The initial energy measurement at the beginning of the frame FRX and subsequent comparison with the current energy value E(t) facilitates a particularly easy implementation.

Figure again in the form of a second variation of the embodiment 1, by means of the comparison determination threshold at time t ₅ S is transgression of a difference △ E2 _t5. Since the threshold S is overtaken by the difference ΔE2 _t5 , the first time base sync1 is erased. The reception of the third symbol Sym3 is terminated by the erasure of the first time base sync1. First time base sync1 erased by the time t following the one indicated by arrow _5. In addition, in the case of the first time base sync1 erasure, erasure of the received bit/data can be performed. An idle mode ID follows the erase event of the first time base sync1.

Performing a new synchronization of one of the preambles of the higher energy signal FSI after the idle mode ID and for listening to one of the phases LI in the transmit channel, wherein the new symbols Sym1' and Sym2' for the new preamble A second time base sync2 is determined.

In Figure 2, a node of a wireless network is schematically represented by a block diagram. This node is preferably designed to comply with the industry standard IEEE 802.15.4. The node has an antenna 900 for receiving RF radio signals, a receiver 100 (RX) connectable to the antenna 900, one transmitter 400 (TX) connectable to the antenna 900, and one of the receivers 100 Data processor 300, which is shown in Figure 2 as a functional block. Preferably, the receiver 100 is monolithically integrated on a semiconductor wafer. For example, the data processor 300 can be designed as a microcontroller uC. The present invention is directed to a receiver 100, and thus the transmitter 400 and data processor 300 are not shown in greater detail.

The receiver 100 has an input amplifier 110, a local oscillator 120, a mixer 130, an AGC 160 automatic gain control, and an analog to digital (A/D) conversion in the receiving path. 140 and one Digital circuit 150, wherein digital circuit 150 provides the received data at the input of data processor 300. The digital circuit 150 is configured to detect the received data of the frame FRX.

Additionally, the receiver has a synchronization unit 700. The synchronization unit 700 is configured to determine a first time base sync1 by synchronization. Synchronization unit 700 is configured to determine suitable sampling instants for chips, symbol boundaries, a time offset, and/or a frequency offset for the first time base. For synchronization, synchronization unit 700 has a synchronization correlator 710 that is designed, for example, as a cross-correlation filter.

If the receiver 100 receives a preamble, such as first supplying the received signal to the sync correlator 710, the sync correlator 710 performs a correlation between the received signal and the known preamble on the receiver side. The output signal of the sync correlator 710 has a periodic maximum indicating a correlation maximum value in each case. A correlation maximum is formed during the complete or near complete overlap of the received signal contained in the preamble with the associated preamble on the receiver side such that, based on the correlation maximum, Symbol boundaries and conclusions about the sampling moments of the chips.

Digital circuit 150 is configured to demodulate the received signal and detect the data. In addition to using the sequence on the receiver side to despread the received signal, the digital circuit 150 also has a correlator 151. The received signal is correlated by means of correlator 151 using a known PN sequence on the receiver side. The digital circuit performs demodulation, despreading, and detection on the received data of the frame FRX using the first time base sync1.

In addition, the receiver 100 has an evaluation device 10, and the evaluation device 10 is provided. It is used to control the digital circuit 150 and the synchronization unit 700. The evaluation circuit 10 does not require any interaction with the data processor 300 for this purpose. Therefore, the control made by the evaluation circuit is not performed in the physical layer (also referred to as the PHY layer) of the OSI model. The evaluation circuit 10 can be coupled to the data processor 300 via an interface.

The evaluation device 10 includes a destination circuit 200. In the embodiment of FIG. 2, destination circuit 200 can be coupled to automatic gain control 160. Automatic gain control 160 provides an RSSI value at the input of destination circuit 200. The RSSI value is determined by the automatic gain control unit 160 using the signal field strength of the RF radio signal. In a first functional block 210 of the destination circuit 200, a first energy value E(t-1), E(t-2) and a second energy value E are determined by averaging the four RSSI values. (t). In a second functional block 220 of the destination circuit 200, a difference ΔE1(t), ΔE2(t) is determined corresponding to equations (1) and (3). In a third function block 230 of one of the destination circuits 200, the differences ΔE1(t), ΔE2(t) are compared with the threshold S. If the difference ΔE1(t), ΔE2(t) exceeds the threshold S, the destination circuit 200 outputs a first error signal er1. The threshold S can be adjusted by the data processor 300 by means of the signal vs3. The comparison can be activated and deactivated by the destination circuit 200 by the control signal en3.

The evaluation device 10 additionally has a control circuit 600 that can input a first error signal er1 at the input of the control circuit 600. Control circuit 600 can be coupled to synchronization unit 700 for controlling synchronization unit 700. In order to initiate a first synchronization, the control circuit 600 triggers the activation of the synchronization unit 700 by the control signal en1. The previous time is erased synchronously because the control circuit 600 transmits an erase signal cl1 to the sync unit 700. If the time base has been determined by the synchronization unit 700 Sync1, sync2, the time base sync1, sync2 are recorded, because the control circuit 600 can activate another synchronization by the control signal en1.

In the embodiment of FIG. 2, control circuit 600 further controls digital circuit 150 by control signal en2 and erase signal cl2. The reception of the current frame can be aborted by means of the control signal en2. Any bit that has been received can be erased by means of the erase signal cl2.

3 and 4 illustrate an embodiment in which one of the received signal quality values QW1(t) or QW2(t) is continuously determined during reception of a frame FRX. For example, the quality values QW1(t), QW2(t) can be determined based on the signal to noise ratio. In the embodiment of the invention of Figs. 3 and 4, the quality values QW1(t), QW2(t) are determined based on the maximum value of the output signal of one of the correlators.

The output signal of the correlator has a maximum value indicating the associated maximum value in each case. A correlation maximum is formed in the case where the sequence of one of the symbols contained in the received signal overlaps completely or nearly completely with the sequence used for correlation on the receiving side. For this reason, conclusions can be drawn regarding the individual symbols and thus also the bits assigned to the symbols, based on, for example, the correlation maximum detected by a threshold detector.

Degradation of quality (i.e., degradation of the characteristics of the transmit channel, such as interference from one of the other nodes, radio signal, multipath propagation, or channel noise) is reduced by one of the output signals that produce a correlation maximum at the output of the correlator. The respective output values of a correlation maximum are then used as the quality measurement Q(t). By evaluating the output signal of the correlator, the quality values QW1(t), QW2(t) can be determined based on one or more quality measurements Q(t).

A first embodiment variation and a second embodiment are also provided for FIG. 3. Change form.

In the variation of the first embodiment of FIG. 3, a quality value QW1(t) corresponds to a current quality measurement Q(t) such that the following formula applies: QW1(t)=Q(t) (5)

In this first embodiment variant of Fig. 3, a quality threshold SQ1(t) is calculated, wherein the following applies: SQ1(t) = Q(t-3)/2 (6)

In this context, the time variable quality threshold is the SQ(t) assigned to the time t of the current quality value QW1(t). The product quality measurement Q(t-3) is the third time leading of the current product quality measurement Q(t).

For the quality value QW1(t) and the quality threshold SQ1(t), a larger/smaller comparison is performed and it is determined whether the quality value QW1(t) is lower than the quality threshold SQ1(t). Between the current product quality measurement Q(t) and the third preamble Q(t-3), the other two quality measurements Q(t-1) and Q(t-2) are determined, however, in Figure 3 The other two values are not considered for comparison in the first embodiment variant.

For example, for time t ₄ , the following formula applies: QW1 _t4 = Q _t4 (7)

And SQ1 _t4 = Q _t1 /2 (8)

The quality value QW1(t) is compared with the quality threshold SQ1(t). If the quality value QW1 _t4 falls below the quality threshold SQ1 _t4 during time t ₄ , the first time base sync1 is erased during reception of the frame FRX. After an idle mode ID and for listening to one of the phases LI in the transmission channel, synchronization for determining one of the second time base updates is started.

In a variation of the second embodiment of FIG. 3, a quality value QW2(t) is determined by the addition of the current quality measurement Q(t) and the previous time quality measurement Q(t-1). The following applies: QW2(t)=Q(t)+Q(t-1) (9)

In a variation of the second embodiment of FIG. 3, a time variable quality threshold SQ2(t) corresponds to one of the current quality measurement values Q(t) (time) third preamble Q(t-3), Make the following formula applicable: SQ2(t)=Q(t-3) (10)

For example, for time t ₄ , the following formula applies: QW2 _t4 = Q _t4 + Q _t3 (11)

And SQ2 _t4 = Q _t1 (12)

The quality value QW2(t) is compared with the quality threshold SQ2(t). If the quality value QW2 _t4 falls below the quality threshold SQ2 _t4 during time t ₄ , the first time base sync1 is erased during reception of the frame FRX. After an idle mode ID and for listening to one of the phases LI in the transmission channel, synchronization for determining one of the second time base updates is also started here.

Figure 3 shows how the quality measurements Q _t1 and Q _t2 are determined in one of the high quality regions HQ. However, the product quality measurements C _t3 and Q _t4 are determined in one of the lower quality regions LQ. Between the time t ₃ and t _4, another node transmitting one symbol symIO, which interferes with the previous symbol frame FRX symRX information of (k-1), symRX ( k) received by the receiver.

When the quality values QW1(t), QW2(t) fall below the quality thresholds SQ1(t), SQ2(t), the trigger has a skirt reset signal RS at times t _y1 and t _y2 . Causes the reception of the current frame FRX to be aborted. The symbols symRXO, symRX1 of the follow-up reset signal RS of the other node can be used for synchronization of a second time base.

Alternatively lines may be used to provide a constant quality of a predetermined threshold SQ _c. In this alternative embodiment variant, the quality value QW1(t) corresponds to the current quality measurement Q(t) such that the following equation is equally applicable: QW1(t)=Q(t) (13)

Constant quality threshold SQ _c and then continue to perform a comparison of a constant quality threshold for the current quality of SQ _c value QW1 (t) promotion of a particularly simple embodiment.

In the embodiment of Figure 4, only the evaluation device 10' is changed compared to Figure 2. The evaluation device 10' of FIG. 4 has a decision circuit 500 to which the input of the decision circuit 500 can be connected. For example, the output signal of correlator 151 of digital circuit 150 is applied to the input of decision circuit 500. The determination circuit 500 has a plurality of functional blocks, wherein the quality measurement value (Q) t, the quality value QW1(t), QW2(t) according to one of the formulas (5) or (9), and according to the formula (6) Or one of (10) determines the quality threshold SQ1(t) and/or SQ2(t). Decision circuit 500 is configured to compare quality values QW1(t), QW2(t) with associated quality thresholds SQ1(t) and/or SQ2(t). If the quality values QW1(t), QW2(t) fall below the associated quality threshold SQ1(t) and/or SQ2(t), the decision circuit 500 outputs a second error signal er2. Using the second error signal er2, the control circuit controls to suspend reception of a current frame FRX, erase the first time base sync1, and begin to determine synchronization of a second time base sync2, such as illustrated in the previous figures. Control signal en4 setting data processor 300 to activate or deactivate decision circuit 500.

In a variation of the first embodiment of FIG. 4, the evaluation device 10' may only have the decision circuit 500. In this first embodiment variant of Fig. 4, the evaluation of the RSSI value is not performed.

In a second embodiment variant of FIG. 4, the evaluation device 10' has both a decision circuit 500 and a destination circuit 200. In order to be able to evaluate the first error signal er1 of the destination circuit 200 and the second error signal er2 of the decision circuit 500 in a combined manner, the control circuit 600 has a logic 610 on which the error signals er1 and er2 are applied. In the embodiment of Figure 4, the logic is designed to be an OR operation. The OR operation causes the difference ΔE1(t) or ΔE2(t) to exceed the threshold S, or if the quality values QW1(t) and/or QW2(t) fall below the quality threshold SQ1 ( t), SQ2(t), the first time base sync1 is erased and an update synchronization is completed. Control circuit 600 can additionally have a state machine 620 for the process steps of controlling the output of control signals eu1, en2 and erase signals cl1, cl2 over time.

The invention is not limited to the embodiment variants shown in Figures 1 to 4. For example, one of the wireless networks for one of the industry standards (Bluetooth, WLAN) can be provided. For example, the receiver can also be modified to place other functional blocks in the middle of the receiver. However, the functionality of the node according to Figure 4 can be used particularly advantageously for one of the industry standard IEEE 802.15.4 wireless networks.

10‧‧‧Evaluation device

10'‧‧‧Evaluation device

100‧‧‧ Receiver

110‧‧‧Input amplifier

120‧‧‧Local Oscillator

130‧‧‧ Mixer

140‧‧‧ analog to digital converter

150‧‧‧ digital circuit

151‧‧‧ correlator

160‧‧‧Automatic gain control

200‧‧‧destination circuit

210‧‧‧ functional square

220‧‧‧ function square

230‧‧‧ function square

300‧‧‧data processor

400‧‧‧transmitter

500‧‧‧Decision circuit

600‧‧‧Control circuit

610‧‧‧Logic

620‧‧‧ state machine

700‧‧‧Synchronization unit

710‧‧‧Synchronization correlator

900‧‧‧Antenna

The invention is described in more detail in the following figures using the representation of the examples, as follows: Figure 1 is a schematic diagram of one of the determined energy values, Figure 2 is a schematic block diagram of one of the nodes of a wireless network, Figure 3 is a schematic diagram of one of the determined quality values, and Figure 4 is a node of a wireless network A schematic block diagram of another development form.

10‧‧‧Evaluation device

100‧‧‧ Receiver

110‧‧‧Input amplifier

120‧‧‧Local Oscillator

130‧‧‧ Mixer

140‧‧‧ analog to digital converter

150‧‧‧ digital circuit

151‧‧‧ correlator

160‧‧‧Automatic gain control

200‧‧‧destination circuit

210‧‧‧ functional square

220‧‧‧ function square

230‧‧‧ function square

300‧‧‧data processor

400‧‧‧transmitter

600‧‧‧Control circuit

700‧‧‧Synchronization unit

710‧‧‧Synchronization correlator

900‧‧‧Antenna

Claims (15)

A method for a receiver, comprising: synchronizing a received signal to determine a time base, the time base defining a temporal reference for data detection; and based on a signal strength of the received signal Determining one of the first values of the received (RSSI) value to determine a first energy value of the received signal; determining a second energy value of the received signal based on the second group of one of the RSSI values of the received signal; determining a difference between the first energy value and the second energy value; determining a quality value of the received signal by correlating segments of the received signal with a sequence of segments Value); and if one or more of the following conditions are true, the time base is redefined: the difference exceeds a predetermined energy threshold; and the quality value is below a predetermined quality threshold. The method of claim 1, further comprising: receiving another signal; and synchronizing the another received signal to determine another time base, the other time base defining another temporal reference for data detection. The method of claim 1, wherein the difference is determined by subtracting the first energy value from the second energy value. The method of claim 1, wherein the predetermined energy threshold is determined by using the first energy value of the received signal and a previous value of the second energy value. The method of claim 1, wherein the predetermined value threshold is used The previous value of the quality value of the received signal is determined. A wireless communication device comprising: an antenna; and a receiver coupled to the antenna, the receiver configured to: synchronize a received signal to determine a time base, the time base defined for data detection a temporal reference; determining a quality value of the received signal by correlating a segment of the received signal with a segment of the sequence, the quality value including a value of a signal to noise ratio associated with the signal; and if When the quality value is below a predetermined quality threshold, the time base is redefined. The apparatus of claim 6, wherein the receiver is further configured to: receive another signal; and synchronize the another received signal to determine another time base, the other time base defining another temporal state for data detection reference. The apparatus of claim 6, wherein the receiver is further configured to: determine a first energy value of the received signal based on the first group of one of a signal strength indication (RSSI) value of the received signal; A second set of RSSI values of the received signal determines a second energy value of the received signal; and wherein the difference is determined by subtracting the first energy value from the second energy value. The device of claim 6, wherein the predetermined energy threshold is obtained by using the first energy value of the received signal and a previous value of the second energy value To make a decision. The apparatus of claim 6, wherein the predetermined value threshold is determined by using a previous value of the quality value of the received signal. An one or more computer readable non-transitory storage mediums comprising configured logic to perform the steps of: synchronizing a received signal to determine a time base, the time base defining a temporal reference for data detection; Determining a quality value of the received signal by correlating a segment of the received signal with a sequence of segments, the quality value including a value of a signal to noise ratio associated with the signal; and if the quality value is lower than A predetermined quality threshold is used to redefine the time base. The computer readable non-transitory storage medium of claim 11, wherein the logic is further configured to: receive another signal; and synchronize the another received signal to determine another time base, the other time base definition for data Another temporal reference for detection. The computer readable non-transitory storage medium of claim 11, wherein the logic is further configured to: determine one of the received signals based on a first group of signal strength indication (RSSI) values of the received signal An energy value; determining a second energy value of the received signal based on the second group of one of the RSSI values of the received signal; and wherein the difference is obtained by subtracting the first energy from the second energy value value To make a decision. The computer readable non-transitory storage medium of claim 11, wherein the predetermined energy threshold is determined by using the first energy value of the received signal and a previous value of the second energy value. The computer readable non-transitory storage medium of claim 11, wherein the predetermined value threshold is determined by using a previous value of the quality value of the received signal.