U.S. patent application number 14/571827 was filed with the patent office on 2016-06-16 for cellular up-link harmonic spurs mitigation in wi-fi and bluetooth receivers.
The applicant listed for this patent is Rotem Avivi, Assaf Gurevitz, Assi Jakoby, Bruno Jechoux, Shimon Solodkin. Invention is credited to Rotem Avivi, Assaf Gurevitz, Assi Jakoby, Bruno Jechoux, Shimon Solodkin.
Application Number | 20160173209 14/571827 |
Document ID | / |
Family ID | 54695480 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160173209 |
Kind Code |
A1 |
Jakoby; Assi ; et
al. |
June 16, 2016 |
CELLULAR UP-LINK HARMONIC SPURS MITIGATION IN WI-FI AND BLUETOOTH
RECEIVERS
Abstract
Described herein are technologies related to an implementation
of harmonic spurs mitigation in a receiver of a portable
device.
Inventors: |
Jakoby; Assi; (Herzelia,
IL) ; Gurevitz; Assaf; (Ramat Hasharon, IL) ;
Avivi; Rotem; (Petah-Tiqwa, IL) ; Solodkin;
Shimon; (Beer Sheva, IL) ; Jechoux; Bruno;
(Antibes, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jakoby; Assi
Gurevitz; Assaf
Avivi; Rotem
Solodkin; Shimon
Jechoux; Bruno |
Herzelia
Ramat Hasharon
Petah-Tiqwa
Beer Sheva
Antibes |
|
IL
IL
IL
IL
FR |
|
|
Family ID: |
54695480 |
Appl. No.: |
14/571827 |
Filed: |
December 16, 2014 |
Current U.S.
Class: |
375/346 |
Current CPC
Class: |
H04B 1/10 20130101; H04B
15/06 20130101; H04B 15/00 20130101; H04W 4/80 20180201; H04B 1/109
20130101; H04B 1/7103 20130101; H04B 1/525 20130101; H04B 1/0475
20130101 |
International
Class: |
H04B 15/06 20060101
H04B015/06; H04B 1/04 20060101 H04B001/04; H04W 4/00 20060101
H04W004/00 |
Claims
1. A method of harmonic spur mitigation comprising: receiving of a
radio frequency (RF) signal during an uplink transmission or upon
receipt of an interfering noise from a co-running cellular modem;
low-pass filtering the received RF signal; filtering high frequency
harmonic components of the uplink transmission or the interfering
noise by a notch filter to prevent the high frequency harmonic
components from interfering with the low-pass filtered RF signal;
and demodulating the low-pass filtered RF signal, where the
demodulating further comprises: transforming the low-pass filtered
RF signal from a time-domain into a frequency-domain low-pass
filtered RF signal; determining a residual harmonic frequency
confidence level of at least one metric in the frequency-domain
low-pass filtered RF signal; tone nulling of the at least one
metric in response to the determination of the residual harmonic
frequency confidence level that is below a threshold value; and
decoding symbols based from a plurality of metrics that remain from
the tone nulling.
2. The method as recited in claim 1 further comprising: converting
the received RF signal into a digital received RF signal.
3. The method as recited in claim 1, wherein the determining of the
residual harmonic frequency confidence level includes comparing of
the confidence level to the threshold value.
4. The method as recited in claim 1, wherein the tone nulling
discards tone bins that includes the at least one metric with the
confidence level that is below the threshold value.
5. The method as recited in claim 1, wherein the demodulating of
the low-pass filtered RF signal is implemented in a
time-domain.
6. The method as recited in claim 1, wherein the filtering of the
uplink transmission is implemented at a time-domain front end of a
receiver.
7. The method as recited in claim 1, wherein a decimation filtering
of the received RF signal includes the low-pass filtering of the
received RF signal to produce a channel selected signal.
8. The method as recited in claim 1, wherein the notch filtering is
configured to include an interference center frequency based from a
channel frequency of the uplink transmission.
9. The method as recited in claim 1, wherein the notch filter is a
frequency configurable notch filter.
10. The method as recited in claim 1, wherein the uplink
transmission includes one of a 2G, 3G, or an LTE signal.
11. The method as recited in claim 1, wherein the filtering of the
uplink transmission is utilized by a Bluetooth receiver to reduce
an interference level of frequency hops which are out of cellular
interference frequency region.
12. A device receiver comprising: a component configured to receive
a radio frequency (RF) signal during an uplink transmission; a
modem configured to produce the uplink transmission, wherein the
modem is co-running with the component; a decimation filter
configured to low-pass filter the received RF signal and a notch
filter configured to filter the uplink transmission to suppress
higher frequency harmonics that interfere with the low-pass
filtered RF signal; a component configured to transform the
low-pass filtered RF signal from a time-domain to a
frequency-domain low-pass filtered RF signal; an equalizer and
metric extractor configured to determine a residual harmonic
frequency confidence level of at least one metric in the
frequency-domain low-pass filtered RF signal; a tone nulling
component configured to discard the at least one metric in response
to the determination of the residual harmonic frequency level that
is below a threshold; and a forward error correction decoder
configured to decode symbols corresponding to one or more metrics
that were not discarded due to the tone nulling.
13. The device receiver as recited in claim 12, wherein the
decimation and the notch filters are positioned at a time-domain
front end of the device receiver.
14. The device receiver as recited in claim 12, wherein the
decimation filter is configured to down-samples and low-pass filter
the received RF signal to produce a channel selected signal.
15. The device receiver as recited in claim 12, wherein the notch
filter is a frequency configurable notch filter.
16. The device receiver as recited in claim 12, wherein the modem
is a cellular modem configured to transmit the uplink transmission
by a 2G, 3G, or an LTE signal.
17. The device receiver as recited in claim 12, wherein the
equalizer and metric extractor is configured to determine a
plurality of equalized received symbols, wherein the determination
of the residual harmonic frequency confidence level for each metric
is based on the plurality of equalized received symbols.
18. The device receiver as recited in claim 12 further comprising a
complementary code keying (CCK) demodulator/decoding component for
the device receiver that is defined by IEEE 802.11b standard.
19. A method of harmonic spur mitigation in a receiver comprising:
receiving of a radio frequency (RF) signal during an uplink
transmission or upon receipt of an interfering noise from a
co-running modem; low-pass filtering the received RF signal;
filtering the uplink transmission at a time-domain front end of the
receiver to remove high frequency harmonics that interfere with the
low-pass filtered RF signal; transforming the low-pass filtered RF
signal from a time-domain into a frequency-domain RF signal;
determining a residual harmonic frequency confidence level of at
least one metric in the frequency-domain RF signal; tone nulling of
the at least one metric in response to the determination of the
residual harmonic frequency confidence level; and decoding symbols
based from one or more metrics that were not discarded due to the
tone nulling.
20. The method as recited in claim 19, wherein the determining of
the residual harmonic frequency confidence level includes comparing
of the confidence level to a configured threshold.
Description
BACKGROUND
[0001] Wireless communication systems may use one or more channels
to transfer data between a transmitter and receivers. These
communication systems may operate according to a set of standards
defined by the Institute of Electrical and Electronics Engineers
(IEEE) 802.11 committee for Wireless Local Area Network (WLAN)
communication.
[0002] During the transfer of data between the transmitter and
receivers, multipath problems and other conditions such as a
presence of harmonic spurs may affect the reception of data
packets. For example, the presence of the harmonic spurs that may
mix with the receiving of the data packets may cause problems with
signal detecting, amplifier gain adjustment, and signal decoding.
To this end, the wireless communication systems employ various
techniques to solve these problems and conditions.
[0003] For example, a linear amplifier design and/or Time Division
Multiplexing (TDM) have been effectively implemented to mitigate
these harmonic spurs. However, designing linear amplifiers and the
use of the TDM may be more complicated and costly for a frequency
varying harmonic spurs.
[0004] As such, there is a need for a lower cost and effective
solution to address the above mentioned problems, i.e., mitigation
of harmonic spurs at the receiver of the portable device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates an example scenario that implements
harmonic spurs mitigation in a portable device.
[0006] FIGS. 2A and 2B illustrate example block diagrams of a
portable device receiver in accordance with implementations
described herein.
[0007] FIG. 3 illustrates an example illustration of mitigating
harmonic spurs in accordance with implementations described
herein.
[0008] FIG. 4 illustrates an exemplary process for implementing
harmonic spurs reduction in accordance with implementations
described herein.
[0009] FIG. 5 illustrates an exemplary process for implementing
harmonic spurs reduction in accordance with implementations
described herein.
DETAILED DESCRIPTION
[0010] Described herein is a technology for implementing a harmonic
spurs reduction in a receiver of a portable device. For example,
the receiver of the portable device receives a radio frequency (RF)
signal that includes a Wi-Fi data packet. In this example, the
receiving of the RF signal is co-running with an uplink cellular
transmission from a cellular modem within the same device.
[0011] To mitigate harmonic spurs effect of the co-running uplink
cellular transmission, or any other known spurs in the system, to
the receiving of the RF signal, a notch filter is configured to
filter the interfering harmonic frequencies of the co-running
uplink cellular transmission, which may affect the de-sensitivity
of the receiver of the portable device. For example, the notch
filter may be configured to operate at interfering center frequency
to eliminate the harmonic spurs produced by the uplink cellular
transmission.
[0012] With the filtered uplink cellular transmission, the received
RF signal is transformed from a time-domain into a frequency-domain
RF signal. At the frequency-domain, a residual harmonic frequency
confidence level of at least one metric in the frequency-domain RF
signal is determined. For example, the frequency-domain RF signal
may include tone bins with corresponding metrics. In this example,
the residual harmonic frequency confidence level for each metric
associated with the tone bins is determined. Thereafter, a tone
nulling of the metric with the residual harmonic frequency
confidence level that is below a configured threshold is performed.
For example, the tone nulling includes discarding of the metric
which fails to satisfy the configured threshold. In this example,
the rest of the metrics are then processed for decoding to produce
decoded bits.
[0013] FIG. 1 is an example scenario 100 that utilizes a harmonic
spurs mitigation in a receiver circuitry or system of a portable
device. The scenario 100 shows a portable device 102 with an
antenna 104, and another portable device 106 with an antenna
106.
[0014] The portable devices 102 or 106 may include, but is not
limited to, a tablet computer, a netbook, a notebook computer, a
laptop computer, mobile phone, a cellular phone, a smartphone, a
personal digital assistant, a multimedia playback device, a digital
music player, a digital video player, a navigational device, a
digital camera, and the like.
[0015] The portable device 102, for example, may communicate with
the other portable device 106 in a network environment. The network
environment, for example, includes a cellular network configured to
facilitate communications between the portable device 102 and the
other portable device 106. During this cellular network
communications, cellular uplink transmissions, for example, from
the portable device 102 may interfere with its co-running of
Bluetooth (BT) and Wi-Fi communication features. Thus, the
implementations described herein may facilitate the harmonic spurs
mitigation, for example, of the interfering cellular uplink
transmissions or any interfering noise received by the receiver
(e.g., harmonics from a circuit board) to BT and Wi-Fi wireless
communications. In the above cellular network, a signal bandwidth
(BW) for 2G, LTE PUCCH, or PUSCH (with <4 RB allocation) signals
is relatively low compared to the Wi-Fi BW. As such, in the
receiver circuitry or system of the portable devices 102 or 106, a
time-domain filtering of the cellular interference may be performed
by applying a frequency configurable notch filter (not shown) in
its time-domain front end. Furthermore, a metric scaling and tone
nulling may be further implemented at the frequency-domain end
portion of the receiver circuitry. The time-domain notch filtering,
for example, may facilitate acquisition of the Wi-Fi signals in the
presence of cellular interference, while the frequency-domain tone
nulling may allow for finer granularity of reducing the remaining
interference energy in the Wi-Fi signals.
[0016] FIGS. 2A and 2B are example schematic block diagrams of a
portable device receiver 200 as described in present
implementations herein. The portable device receiver 200 may
include a radio frequency (RF) module 202, a Wi-Fi modem 204, a BT
modem 206, and a cellular modem 208 to enable the device to
communicate over the cellular network. Furthermore, the portable
device receiver 200 shows the Wi-Fi modem 204 to include an
analog-to-digital converter (ADC) 210, a decimation/notch filters
212, a Wi-Fi acquisition component 214, a digital crystal
oscillator (DCO) 216 (It is to be understood that other oscillators
may be implemented, such as a transmit oscillator or XO, and other
oscillators such as TXCO, XTAL, etc.), a Fast Fourier Transform
(FFT) 218, an equalizer plus metric extractor 220, a metric
scaling/nulling 222, a forward-error-correction (FEC) decoder, and
decoded bits 226. It is also to be understood that portable
receiver 200 may include one or more processors and one or more
memory components.
[0017] As an example of present implementations herein, an uplink
transmission from the cellular modem 208 may produce interfering
harmonic frequencies to the co-running receiving operations of the
Wi-Fi modem 204 and the BT modem 206. In this regard, the
combination of notch filtering and metric scaling/tone nulling may
be implemented in the Wi-Fi modem 204, while the time-domain notch
filtering may be enough to suppress the harmonic distortions in the
operation of the BT modem 206.
[0018] During the uplink transmissions by the cellular modem 208
using, for example, 2G, 3G or LTE carrier frequency, RF signals (or
Wi-Fi signals) may be received at the same time by the co-running
Wi-Fi modem 204 through the Wi-Fi acquisition component 214. The
received RF signals, for example, passes through the RF module 212
where the received RF signals may be amplified by a low noise
amplifier (not shown) to provide an amplified received or inbound
RF signals. In this example, the amplified received RF signals may
be further down-converted by a down-conversion module (not shown)
and band-pass filtered to produce low intermediate frequency (IF)
signals in the RF module 202.
[0019] The ADC 210 may then convert the low IF signals from an
analog domain into digital domain to produce digital low IF
signals. At this stage, the digital low IF signals may be affected
by the interfering harmonic frequencies due to the uplink
transmissions from the cellular modem 208 or any other spur
interference. The interfering harmonic frequencies, for example,
produces a de-sensitivity in the Wi-Fi modem 104. In this example,
the digital low IF signals may still be reconstructed and/or
demodulated; however, the harmonic frequencies from the uplink
transmissions may cause the de-sensitivity of the Wi-Fi modem 104
to reach about 40 dB. By using the combination of the notch
filtering and metric scaling/nulling as described herein, the
de-sensitivity of the Wi-Fi modem may improve up to 35 dB, which
may result to improved de-sensitivity of 5 dB.
[0020] As an example of present implementations herein, the
decimation/notch filter 212 is implemented at time-domain front end
of the receiver block diagram 100. The decimation filter of the
decimation/notch filter 212 may perform a low-pass filtering of the
received digital low IF signals and thereafter down-samples the
digital low IF signals to provide channel selected signals
[0021] On the other hand, the frequency configurable notch filter
of the decimation/notch filter 212 may be configured to cancel the
interfering harmonic frequencies due to the uplink transmissions
from the cellular modem 208. For example, the Wi-Fi modem 204 may
facilitate configuration of the notch filtering to operate at an
interference center frequency. In this example, the Wi-Fi modem 204
may derive this configuration of the notch filter based upon
Non-Real Time (NRT) indication of a) 2G-GSM, GPRS, EDGE channel
frequency, 3G for IEEE 802.11ac where the Wi-Fi bandwidth is 80/160
MHz; and b) LTE channel frequency. Furthermore, the Wi-Fi modem 204
may utilize Real Time (RT) information indicating: a) Cellular is
transmitting GSM, GPRS, EDGE, b) 2G transmission indication+TX
center frequency (in case of hopping), and c) Cellular is
transmitting LTE PUCCH+PUCCH index or LTE PUSCH+allocated RB, when
configuring the notch filter of the decimation/notch filter 212.
Furthermore still, the Wi-Fi modem 204 may utilize the RT/NRT
information from 2G/LTE such as whether the 2G is transmitting or
not, the 2G carrier frequency, etc. in understanding the spur
frequency and the respective time when interfering harmonic
frequency is present.
[0022] From the above information, the Wi-Fi modem 204 may decide
the frequency range where the harmonic spurs fall in the 2.4 GHz/5
GHz Wi-Fi bands. For example, the Wi-Fi modem 204 may configure the
notch filtering to include an operating center frequency of the
interfering harmonic spurs. In this example, the Wi-Fi modem 204
may further activate the metric tone nulling or scaling based on
expected interference level at the frequency, and based on the
remaining frequency bins (i.e., output of FFT 218) which are
interfered by the cellular uplink transmission.
[0023] With continuing reference to FIG. 2A, the DCO 216 is
utilized, for example, as a digitally controlled
voltage-to-frequency converter. For example, the DCO 216 produces a
frequency variation in response to a control voltage, which is
facilitated by the channel selected signals. In this example, the
DCO 216 provides the frequency variation equivalence of the channel
selected signals to the FFT 218.
[0024] The FFT 218 may perform an algorithm that converts the
received channel selected signals from time domain to frequency
domain. For example, the channel selected signals include an array
of time-domain waveform samples. In this example, the FFT 218
converts time-domain waveform samples into frequency-domain
spectrum samples such as a plurality of received symbols. The
frequency-domain spectrum samples may include tone bins with
corresponding metrics to define a data packet.
[0025] The equalizer plus metric extractor 220 receives the
transformed channel selected signals and determines a plurality of
equalized received symbols. Based on the plurality of equalized
received symbols, the metric extractor may provide a corresponding
plurality of metrics. For example, an equalized symbol may
correspond to one or more metrics. In this example, the
corresponding one or more metrics are further scaled or nulled by
the metric scaling/nulling 222 upon a determination of a confidence
level of the residual harmonic frequency that may be present in the
corresponding one or more metrics. For example, the determination
of the confidence level utilizes a threshold to determine whether
or not to discard the said one or more metrics at the FEC decoder
224.
[0026] As an example implementation described herein, the metric
scaling/nulling 222 is configured to eliminate residual harmonic
interference present in the channel selected signal prior to the
FEC decoding. For example, the time domain notch filtering as
discussed above may facilitate receiving of the Wi-Fi signals in
the presence of the cellular interference from the cellular modem
208. In this example, the metric scaling/nulling 222 provides for
finer granularity of reducing the remaining interference energy at
the output of the equalizer plus Wi-Fi metric extractor 220, which
feeds the FEC decoder 224. The metric scaling/nulling 222, unlike
the decimation/notch filtering, is implemented at frequency-domain
end of the portable device receiver 200.
[0027] In an implementation, the metric scaling/nulling 222
processes the corresponding one or more metrics for each equalized
symbol. In this example, the processing may include elimination or
tone nulling of the one or more metrics that contains residual
harmonic frequency. In other words, an algorithm may be performed
to determine presence of residual harmonic frequency on the one or
more metrics. The algorithm may include the threshold level to
determine the residual harmonic frequency confidence level for the
one or more metrics. For example, the metric scaling/nulling 222
may discard or scale the one or more metrics with residual harmonic
frequency confidence level that is below the configured threshold.
In this example, the tone bins that contains the discarded one or
more metrics may be nulled prior to the FEC decoding.
[0028] With the given harmonic frequency suppression provided by
the decimation/notch filter 212 and the metric scaling/nulling 222,
the FEC decoder 224 recovers and demodulates the digital data from
the channel selected signals. In this example, the FEC decoder 224
includes the decode bits 226 as an output. The decode bits 226 may
be free from harmonic frequency interferences.
[0029] With continuing reference to FIG. 2A, the BT modem 206 may
utilize an adaptive frequency hopping (AFH) based on above
discussed harmonic interference suppression. Typically, the AFH
allows the BT modem 206 to adapt to the environment by identifying
fixed sources of interference and excluding them from the list of
available channels. This process of re-mapping may involve
reduction of the number of channels to be used by the BT modem 206.
Block 228 represents how the BT modem 206 selects AFH per cellular
harmonics information. An example further details this in the
description of process flowchart 500 discussed below.
[0030] In an implementation, the AFH may set aside channel or
channels that include harmonic spurs. For example, the notch
filtering at the decimation/notch filter 212 may discard one or
more channels that contain interfering harmonic spurs. In this
example, the BT modem 206 may utilize the channels that were not
affected by the interfering harmonic frequencies from the cellular
modem 208.
[0031] Although the example portable device receiver 200
illustrates in a limited manner basic components of the receiver of
the portable device, other components such as battery, one or more
processors, SIM card, etc. were not described in order to simplify
the embodiments described herein.
[0032] FIG. 2B is another example implementation of the portable
device receiver 200 when using the 802.11b standard. As shown, a
complementary code keying (CCK) demodulator/decoding 230 replaces
the FFT 218, the equalizer plus metric extractor 220 and the metric
scaling/nulling 222 that were previously described in FIG. 2A
[0033] Because the 802.11b standard does not include the FFT 218 in
its circuitry, the decimation/notch filter 212 may be implemented
even without the metric scaling/nulling 222. That is, the unwanted
harmonic frequencies from the co-running uplink transmission may be
filtered and/or eliminated by the decimation/notch filter 212 as
discussed above.
[0034] In an implementation, block 232 may not be limited to the
cellular modem 208 as described in FIG. 2A above. For example, in
digitally enhanced cordless telecommunications (DECT), the block
232 may include wireless interference technology other than the
cellular uplink transmission interference as described above. In
this example, similar procedure such as the notch filtering may be
implemented to reduce the interference from the wireless
interference technology.
[0035] FIG. 3 is an example illustration of harmonic spurs
mitigation in accordance with implementations described herein.
FIG. 3A shows a Wi-Fi packet 300, a cellular interference signal
302, a notch filter signal 304, and a metric scaling/tone nulling
signal 306.
[0036] In an implementation, the Wi-Fi packet 300 may be received
through the Wi-Fi acquisition component 214 as discussed in FIG. 2A
above. On the other hand, the cellular interference 302 may be
generated by the uplink cellular transmission from the cellular
modem 208.
[0037] Based from the RT/NRT information as discussed above, the
frequency configurable notch filter may produce the notch filter
signal 302. The notch filter signal 304, for example, is a notch
filtered cellular interference signal 302. In other words, the
notch filter signal 304 may not include the interfering higher
harmonic frequencies of the cellular interference signal 302.
[0038] In an implementation, the combination of the notch filtering
and the metric scaling/tone nulling produces the metric
scaling/tone nulling signal 306. In this implementation, the metric
scaling/tone nulling signal 306 further eliminates residual
harmonic frequencies due to the cellular interference signal
302.
[0039] With continuing reference to FIG. 3, the Wi-Fi packets 300-2
and 300-4 are successive data packets that may be received during
the uplink cellular transmission. In an implementation, the notch
filter signal 304 and the metric scaling/tone nulling signal 306
may adapt the same configuration as discussed above.
[0040] FIG. 4 shows an example process flowchart 400 illustrating
an example method for harmonic spurs mitigation in Wi-Fi and BT
receivers of a portable device. The harmonic spurs, for example,
are produced by co-running uplink transmission from the cellular
modem within the same portable device. The order in which the
method is described is not intended to be construed as a
limitation, and any number of the described method blocks may be
combined in any order to implement the method, or alternate method.
Additionally, individual blocks may be deleted from the method
without departing from the spirit and scope of the subject matter
described herein. Furthermore, the method may be implemented in any
suitable hardware, software, firmware, or a combination thereof,
without departing from the scope of the invention.
[0041] At block 402, receiving of RF signals during an uplink
cellular transmission is performed. For example, the Wi-Fi modem
204 receives the RF signals through the RF module 202. In this
example, the received RF signals may undergo different electronic
processing such as amplification, down-conversion, and band-pass
filtering to produce a low IF signal. Furthermore, the ADC 210 may
convert the analog low IF signals into digital low IF signals.
[0042] At block 404, filtering the uplink cellular transmission by
a notch filter is performed. For example, the decimation/notch
filter 212 includes the frequency configurable notch filter to
cancel higher frequency harmonics from the uplink cellular
transmission. The uplink cellular transmission is produced by the
cellular modem 208, which is co-running with the Wi-Fi and BT
receiving operations.
[0043] At block 406, transforming the received RF signal from a
time-domain to a frequency-domain RF signal is performed. For
example, the channel selected signals include an array of
time-domain waveform samples. In this example, the FFT 218 converts
the time-domain waveform samples into frequency-domain spectrum
samples. The frequency-domain spectrum samples may include Nyquist
sampling of the time-domain input signals.
[0044] At block 408, determining a residual harmonic frequency
confidence level of at least one metric in the frequency-domain RF
signals is performed. For example, the output of the FFT 218 is
received by the equalizer plus metric extractor 220 in order to
determine and produce the plurality of equalized received symbols.
In this example, the plurality of equalized received symbols
include one or metrics that may carry the residual interfering
harmonic frequencies. Thus, an algorithm is performed in order to
determine the residual harmonic frequency level of the one or more
metrics.
[0045] At block 410, nulling the metric in response to the
determining of the residual harmonic frequency confidence level
that is below a configured threshold is performed. For example, the
metric scaling/nulling 222 may be configured to discard the tone
bins and corresponding metrics in a case where the residual
harmonic frequency confidence level of the corresponding metric is
below the configured threshold.
[0046] At block 412, decoding symbols based from one or more
metrics that were not discarded due to the tone nulling is
performed. In a case where the one or more metrics with no residual
harmonic frequency are identified, the FEC decoder 224 may be
configured to produce the decode bits 226.
[0047] In an implementation, the BT modem 206 may select channels
through AFH process by taking into consideration the channel or
channels with no interfering harmonic frequencies as discussed
above.
[0048] FIG. 5 shows an example process flowchart 500 illustrating
an example method for Bluetooth (BT) protection and adaptive
frequency hopping (AFH). Process 500 may be implemented for example
in block 228 of BT modem 206 described above. The order in which
the method is described is not intended to be construed as a
limitation, and any number of the described method blocks may be
combined in any order to implement the method, or alternate method.
Additionally, individual blocks may be deleted from the method
without departing from the spirit and scope of the subject matter
described herein. Furthermore, the method may be implemented in any
suitable hardware, software, firmware, or a combination thereof,
without departing from the scope of the invention.
[0049] At block 502, activating a BT mode of a device is performed.
For example, the BT modem 206 is activated to perform the BT mode
of wireless communication. In this example, the BT modem 206 is
co-running with the cellular 2G/LTE 208.
[0050] At block 504, calculating unwanted harmonic frequencies from
a co-running uplink cellular transmission is performed. For
example, the block 228 implements an algorithm that measures and
determines the unwanted harmonic frequencies due to the uplink
cellular transmission from the co-running cellular 2G/LTE 208.
[0051] At block 506, implementing the adaptive frequency hopping
(AFH) is performed. For example, AFH channel frequency negotiation
is performed with BT connected peer devices. In this example, the
AFH channel frequency negotiation may be based upon the calculated
unwanted harmonic frequencies in block 504 above.
[0052] At block 508, communicating through a AFH channel is
performed. For example, the AFH channel includes the channel/s with
no unwanted harmonic frequencies.
[0053] The following examples pertain to further embodiments:
[0054] Example 1 is a method of harmonic spur mitigation
comprising: receiving of a radio frequency (RF) signal during an
uplink transmission or upon receipt of an interfering noise;
filtering the uplink transmission or the interfering noise by a
notch filter; and demodulating the received RF signal.
[0055] In example 2, the method as recited in example 1, wherein
the demodulating of the received RF signal further comprises:
transforming the received RF signal from a time-domain into a
frequency-domain RF signal; determining a residual harmonic
frequency confidence level of at least one metric in the
frequency-domain RF signal; tone nulling of the at least one metric
in response to the determination of the residual harmonic frequency
confidence level; and decoding symbols based from a plurality of
metrics that remain from the tone nulling.
[0056] In example 3, the method as recited in example 2, wherein
the determining of the residual harmonic frequency confidence level
includes comparing of the confidence level to a threshold.
[0057] In example 4, the method as recited in example 2, wherein
the tone nulling discards tone bins that includes the at least one
metric with the confidence level that is below a threshold
value.
[0058] In example 5, the method as recited in any of examples 1 to
4, wherein the demodulating of the received RF signal is
implemented in a time-domain.
[0059] In example 6, the method as recited in any of examples 1 to
4, wherein the filtering of the uplink transmission is implemented
at a time-domain front end of a receiver.
[0060] In example 7, the method as recited in any of examples 1 to
4, wherein a decimation filtering of the received RF signal
includes low-pass filtering of the received RF signal to produce a
channel selected signal.
[0061] In example 8, the method as recited in any of examples 1 to
4, wherein the notch filtering is configured to include an
interference center frequency based from a channel frequency of the
uplink transmission.
[0062] In example 9, the method as recited in any of examples 1 to
4, wherein the notch filter is a frequency configurable notch
filter.
[0063] In example 10, the method as recited in any of examples 1 to
4, wherein the uplink transmission includes one of a 2G. 3G, or an
LTE signal.
[0064] In example 11, the method as recited in any of examples 1 to
4, wherein the filtering of the uplink transmission is utilized by
a Bluetooth receiver to reduce an interference level of frequency
hops which are out of cellular interference frequency region.
[0065] Example 12 is a device receiver comprising: a component
configured to receive a radio frequency (RF) signal during an
uplink transmission; a modem configured to produce the uplink
transmission; a decimation and notch filter configured to filter
the uplink transmission to suppress higher frequency harmonics; a
component configured to transform the filtered RF signal from a
time-domain to a frequency-domain filtered RF signal; an equalizer
and metric extractor configured to determine a residual harmonic
frequency confidence level of at least one metric in the
frequency-domain filtered RF signal; a tone nulling component
configured to discard the at least one metric in response to the
determination of the residual harmonic frequency level that is
below a threshold; and a forward error correction decoder
configured to decode symbols corresponding to one or more metrics
that were not discarded due to the tone nulling.
[0066] In example 13, the device receiver as recited in example 12,
wherein the decimation and the notch filters are positioned at a
time-domain front end of the device receiver.
[0067] In example 14, the device receiver as recited in example 12,
wherein the decimation filter down-samples and low-pass is
configured to filter the received RF signal to produce a channel
selected signal.
[0068] In example 15, the device receiver as recited in example 12,
wherein the notch filter is a frequency configurable notch
filter.
[0069] In example 16, the device receiver as recited in example 12,
wherein the equalizer and metric extractor is configured to
determine a plurality of equalized received symbols, wherein the
determination of the residual harmonic frequency confidence level
for each metric is based on the plurality of equalized received
symbols.
[0070] In example 17, the device receiver as recited in any of
examples 12 to 16, wherein the cellular modem is configured to
transmit the uplink transmission by a 2G, 3G, or an LTE signal.
[0071] In example 18, the device receiver as recited in any of
examples 12 to 16 further comprising a complementary code keying
(CCK) demodulator/decoding component for the device receiver that
is defined by IEEE 802.11b standard.
[0072] Example 19 is a method of harmonic spur mitigation in a
receiver comprising: receiving of a radio frequency (RF) signal
during an uplink transmission or upon receipt of an interfering
noise; filtering the uplink transmission at a time-domain front end
of the receiver; transforming the received RF signal from a
time-domain into a frequency-domain RF signal; determining a
residual harmonic frequency confidence level of at least one metric
in the frequency-domain RF signal; tone nulling of the at least one
metric in response to the determination of the residual harmonic
frequency confidence level; and decoding symbols based from one or
more metrics that were not discarded due to the tone nulling.
[0073] In example 20, the method as recited in example 19, wherein
the determining of the residual harmonic frequency confidence level
includes comparing of the confidence level to a configured
threshold.
* * * * *