Patent Grant
8559865
The present disclosure relates generally to apparatus and methods for communication receivers. More particularly the present disclosure relates to jammer detector architectures.
In a conventional communications receiver, there are two conflicting requirements: high sensitivity and high linearity. High sensitivity refers to the receiver characteristic of a low noise figure with high gain so that the receiver is sensitive to a weak signal. A low noise figure LNA provides better sensitivity to the receiver and good SNR for a weak signal. However, a low noise figure LNA with high gain fails to provide adequate SNR in the presence of strong interference (i.e., jammer) because the intermodulation level increases. The intermodulation level increase is due to the low third order intercept point (IP3) and low 1 dB compression point (P1dB) for a high sensitivity receiver.
High linearity refers to the receiver characteristic of a high third order intercept point (IP3) and a high 1 dB compression point (P1dB). A high linearity receiver has improved immunity against strong signals and against strong interferences (i.e., jammers). That is, a high linearity receiver has less distortion (e.g., intermodulation product levels, gain compression, phase non-linearity, AM-PM conversions, etc.) in the presence of strong signals or strong interferences than a high sensitivity receiver. However, a high linearity receiver (i.e., the LNA) has a higher noise figure and lower gain and therefore cannot provide optimal sensitivity and SNR in the presence of a weak jammer or if no jammer appears at all. In a particular input signal environment, to determine the appropriate characteristic of the receiver (high sensitivity versus high linearity) that is needed, a jammer detector coupled to the receiver is used. The jammer detector detects the presence of jammers. Conventional jammer detectors are typically optimized for narrowband, single band operation and do not provide both wideband and narrowband jammer detection for a multiband, multi-standard receiver over a broad frequency range.
Disclosed are a method and apparatus for providing jammer detection in a receiver. In one aspect, the jammer detector for providing the jammer detection is a combination of several complementary jammer detectors, both hardware and software-based. The jammer detector incorporates a narrowband jammer detector (NB JD) to detect inband close in jammers to wanted signal, a wideband jammer detector (WB JD) to detect far off and out of band jammers, and a software jammer detector (SW JD) for detecting concurrent operation jammers. In one aspect, each of the NB JD, WB JD and SW JD has its own optimized threshold (THj). In one aspect, the jammer detector provides both wideband and narrowband jammer detection for a multiband, multi-standard, dual mode receiver over a broad frequency range.
According to one aspect, a jammer detector comprising a wideband jammer detector component for generating a wideband (WB) interrupt signal to indicate the presence of a wideband jammer; a narrowband jammer detector component for generating a narrowband (NB) interrupt signal to indicate the presence of a narrowband jammer; and an interrupt logic module for generating a composite interrupt signal based on at least one of the WB interrupt signal and the NB interrupt signal.
According to another aspect, a device for detecting a jammer comprising a wideband jammer detector for generating a wideband (WB) interrupt signal to indicate the presence of a wideband jammer; a narrowband jammer detector for generating a narrowband (NB) interrupt signal to indicate the presence of a narrowband jammer; an interrupt logic module for generating a composite interrupt signal based on at least one of the WB interrupt signal and the NB interrupt signal; and means for detecting a concurrent operation jammer from a transmitter.
According to another aspect, a wireless communication unit for jammer detection comprising a plurality of receivers for at least one of a plurality of applications; a plurality of transmitters for at least one of the plurality of applications; a wideband jammer detector for generating a wideband (WB) interrupt signal to indicate the presence of a wideband jammer; a narrowband jammer detector for generating a narrowband (NB) interrupt signal to indicate the presence of a narrowband jammer; an interrupt logic module for generating a composite interrupt signal based on at least one of the WB interrupt signal and the NB interrupt signal; a software-based jammer detector for detecting a concurrent operation jammer from one of the plurality of transmitters; and a central software based mechanism for sending a notification of the concurrent operation jammer to at least one of the plurality of receivers.
According to another aspect, a computer-readable medium storing a computer program, wherein execution of the computer program is for: sampling an input signal to generate a sampled input signal; downconverting the input signal to generate a downconverted input signal; sampling the downconverted input signal to generate a sampled downconverted (SD) input signal; comparing the sampled input signal to a wideband threshold THWB, and comparing the SD input signal to a narrowband threshold THNB; generating a wideband (WB) interrupt signal based on the comparison to the THWB, and generating a narrowband (NB) interrupt signal based on the comparison to the THNB; and generating a composite interrupt signal based on one or more of the WB interrupt signal or the NB interrupt signal.
According to another aspect, a method for detecting a jammer comprising sampling an input signal to generate a sampled input signal; downconverting the input signal to generate a downconverted input signal, and sampling the downconverted input signal to generate a sampled downconverted (SD) input signal; comparing the sampled input signal to a wideband threshold THWB, and comparing the SD input signal to a narrowband threshold THNB; generating a wideband (WB) interrupt signal based on the comparison to the THWB, and generating a narrowband (NB) interrupt signal based on the comparison to the THNB; and generating a composite interrupt signal based on one or more of the WB interrupt signal or the NB interrupt signal.
It is understood that other aspects will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described various aspects by way of illustration. The drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
a illustrates an example coexistence management system.
b illustrates an example of a dual mode receiver.
a-6d illustrate examples of jammer frequency maps.
a illustrates the output voltage (Vout) versus input power (Pin) of the wanted signal and the jammer signal as function of frequency response of the receiver at different points in the receive chain and output power (Pout) of the wanted signal and the jammer versus frequency as function of frequency response of the receiver at different points in the receive chain with the jammer detector hardware as shown in
b illustrates an example of a hardware implementation of a jammer detector with a wideband jammer detector (WB JD) component and a narrowband jammer detector (NB JD) component and its interrupt logic showing combined interrupt or dedicated interrupt report for each JD.
a illustrates an example of a hardware implementation of a jammer detector comprising a narrowband jammer detector (NB JD) component and one implementation of the wideband jammer detector (WB JD) component.
a illustrates an example implementation for extending detection of jammers within the receiver bandwidth.
b-9d illustrate examples of receiver implementations in accordance with the present disclosure.
a illustrates an example of interrupt sources and status reporting to a jammer detector register.
b illustrates another example of interrupt sources and status reporting to a jammer detector register.
a illustrates an example interrupt and status report from the NB JD and WB JD.
b illustrates another example interrupt and status report from the NB JD and WB JD.
a illustrates an example of a multicom radio mobile telephone with several receivers, transceivers and connectivity technologies and with several integration levels such as high, medium and low attach rates.
b illustrates a hardware JD example, including a combination of a NB JD and a WB JD along with a software JD to cover concurrent operation with the ability to sniff the power supply and wherein the PMIC monitors concurrent operation indirectly or monitors concurrent operation current consumption and provides overall platform current logs.
c illustrates an example of an interference scenario where concurrent radio systems are operating, and the transmitter from one system couples spurious signals into the receiver of another system.
a and 14b illustrate two examples of RF power versus jammer voltage relationships that can be used for adaptive TH.
The detailed description set forth below in connection with the appended drawings is intended as a description of various aspects of the present disclosure and is not intended to represent the only aspects in which the present disclosure may be practiced. Each aspect described in this disclosure is provided merely as an example or illustration of the present disclosure, and should not necessarily be construed as preferred or advantageous over other aspects. The detailed description includes specific details for the purpose of providing a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the present disclosure. Acronyms and other descriptive terminology may be used merely for convenience and clarity and are not intended to limit the scope of the disclosure.
While for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more aspects, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts may be required to implement a methodology in accordance with one or more aspects.
The present disclosure describes a very wideband jammer detection (JD) hardware architecture which protects a very wideband receiver from off-air jammers. In one example, the wideband jammer detector covers a jammer spectrum of at least 4 octaves. A narrowband jammer detector (NB-JD) implemented in the analog baseband circuitry protects against close-in jammer effects such as gain compression and second order intermodulation (IMR2) from jammers that are out of band of the NB-JD. The jammers that are out of band of the NB-JD create third order intermodulation (IMR3) products with jammers that are detected by the NB-JD. A wideband jammer detector (WB-JD) implemented in the receiver front end circuitry protects against inband off-air jammers which are far beyond the NB-JD capability. The NB-JD protects a very wideband receiver against very high power jammers that might generate IMR3 products within the receive band. The NB-JD protects the receiver against jammers that are above its operational BW (bandwidth) by detecting jammers within its detection BW that can generate IMR3 and cross modulation with jammers that are out of its detection BW. In one aspect, the present disclosure describes utilizing two independent thresholds, one for the NB-JD and the another for the WB-JD to optimize the receiver's high sensitivity mode of operation under the following scenarios:
In one aspect, the wideband threshold (THWB) and/or the narrowband threshold (THNB) is selected to optimize the time of a receiver in the highest gain state G0. In one example, the receiver comprises the jammer detectors.
In addition, in one aspect, the present disclosure implements a software based jammer detector (SW-JD) 230 (shown in
In one aspect, the hardware JD interface enables a configurable interface between the JD and the baseband circuitry which defines the interruption source and jammer type. For example, each JD has its own interrupt line, both JDs share the same interrupt, and each JD has its own status bit. The hardware JD interface also enables automatic updates of thresholds based on (serial bus interface) SBI code for gain state and JD status, which saves SBI write operations.
The receive/transmit mapping is based on location using a SW-JD kiosk. In one aspect, a software kiosk provides information to users without permitting modification of the information. The software kiosk maps all transmission power of all concurrent transmissions based on location using the GPS receiver data. It maps all receiver levels of all concurrent receivers and the actual protected receiver based on location using the GPS receiver data. It also maps all power consumption based on all receive/transmit activities based on location using the GPS receiver data. Finally, it maps the operational mode based on all receive/transmit activities based on location using the GPS receiver data. In other aspect the receive/transmit mapping is used in the receive spectrum, transmit spectrum and power consumption as function of receive/transmit location. In other aspect the receive/transmit mapping can be used by operators to evaluate field trials by fetching the data from the receive/transmit unit via the data service channel and conduct a user profile experiment.
a illustrates an example coexistence management system. As shown in
A dual mode receiver toggles between two modes. In one aspect, the two modes include a high sensitivity mode (mode 1) and a high linearity mode (mode 2), and the dual mode receiver toggles between these two modes depending on the input signal environment. If the dual mode receiver is in high sensitivity mode, it may need immediate protection when a strong jammer appears. In one example, such protection is implemented using a fast attack automatic gain control (AGC) circuit. Fast attack refers to a property of the AGC circuit or algorithm which is a rapid gain reduction after the appearance of a strong input signal level (e.g., jammer). Then, when the strong jammer disappears, the dual mode receiver may require a slow release AGC circuit or algorithm to avoid fast toggling between the two modes. Slow release refers to a property of the AGC circuit or algorithm which is a slow gain increase after the disappearance of a strong input signal level (i.e., the strong jammer).
In conventional receiver designs, the AGC mode of operation is triggered by a single jammer detector (JD) designed for narrowband operation over a single radio frequency (RF) band. However, in many wireless scenarios, there are several interfering transmitters operating at various frequency bands, transmit power levels, and modulation schemes. A single jammer detector is not optimal for detecting a variety of jammers over a very wide bandwidth. Yet, there is a need to protect the receiver against all jammers present in the wideband environment.
b illustrates an example of a dual mode receiver 100. For the dual mode receiver, mode 1 has high sensitivity and low linearity characteristics. Mode 2 has high linearity and moderate sensitivity characteristics. Mode 1 employs an LNA with low noise figure, high gain, and low current consumption. Mode 1 is used when a low level jammer or no jammer is present at the receiver input. Mode 2 employs an LNA with lower gain, higher IP3, higher current consumption and lower noise figure. Mode 2 is used when a strong jammer is present in the dual mode receiver input. The transition between the two modes is implemented by an automatic gain control (AGC) circuit or algorithm 220 triggered by a JD Read block 210 which are shown in
In one example, an input RF signal is captured by a receive antenna (not shown) coupled to the dual mode receiver and is sent to the inputs (110, 120 respectively) of both mode 1 LNA and mode 2 LNA for low noise amplification and production of the mode 1 output RF signal and mode 2 output RF signal, respectively. Mode 1 LNA has input 110, and Mode 2 LNA has input 120 as shown in
The selected output RF signal is sent to the mixer/low pass filter (LPF) 130 for frequency downconversion and production of the input baseband signal. As an example the input baseband signal is sent to the analog-to-digital converter (ADC) 140 for conversion to an input digital signal. The input digital signal is then sent to a digital variable gain amplifier (DVGA) 150 for gain adjustment and production of the output digital signal. The output digital signal is then sent to the sample server (SS) module 160 for capturing the data and demodulation and also to the energy estimator (EE) 170 for estimation of the energy of the output digital signal (e.g., receiver output energy).
The AGC circuit or algorithm 220 accepts the jammer detector interrupt bit, as well as the current LNA gain state, current DVGA gain state, and current EE value, as inputs to the AGC circuit. The outputs of the AGC circuit are an updated LNA gain state and an updated DVGA gain state, based on the various AGC inputs. In one example, the outputs of the AGC circuit are directed to one of the two LNAs and the DVGA 150 (shown in
In one aspect, the mode 2 (high linearity mode) LNA has a plurality of gain states. In one example, the mode 2 LNA has three gain states, G1, G2, and G3, in order of decreasing gain and increasing P1dB and IP3 while compromising noise figure. Additionally, mode 2 may have other higher gain states G4, G5 and G6 and even more gain states based on application. In one aspect, in the AGC circuit, the mode 2 LNA gain state depends on the crossing of an AGC switch point. In one example, the mode 1 LNA has a plurality of gain states. One skilled in the art would understand that the quantity of gain states for mode 1 and/or mode 2 can be chosen depending on the particular application and design parameters without affecting the spirit or scope of the present disclosure.
Based upon the state of the jammer detector, the AGC switch points are advanced or retarded, with respect to each other as illustrated in
In another aspect, the AGC switch point table is based on several parameters such as the gain compression point (to mitigate mixer nonlinearities), the ADC saturation point (to mitigate ADC nonlinearities), and the receiver third order intermodulation ratio (IMR3) (to mitigate overall carrier/noise degradation). In one example, the AGC switch points are optimized such that the receiver linearity and sensitivity requirements are met in a jammer-free environment. In the presence of jammers, the AGC switch point values are modified to cause earlier gain switching. The modified AGC switch point values may be adaptive depending on the jammer level.
In one aspect, jammer detector profiles are defined by various radio standards. The jammer detector protects the receiver against gain compression, saturation, cross-modulation (X-MOD) and intermodulation products due to jammers by informing the AGC to change the switch point look up table to mode 2 in a fast attack process.
The condition for generating inband intermodulation products is given by equation (1).
f0=2f1−f2 (1)
where f0 is the desired frequency. Equation (1) defines the maximum frequency of band A that creates intermodulation with band B. As a consequence, if the upper limit of band A is f1, then the upper limit of band B coverage is f2. Thus the wider the NB-JD bandwidth the wider band A and the covered portion of band B is larger. Hence detection of jammers in band A protects against intermodulation products due to jammers in band B. A wider band protection against intermodulation products due to the A and B bands can be obtained with wider band jammer detection in band A. Additionally band A includes the adjacent and alternate jammers frequencies which are detected by the narrowband JD. However, band B is the remaining bandwidth which is not covered by the NB JD even though detection of jammers in band A protects against intermodulation products due to jammers in band B.
In one aspect, the design goal is to maintain the intermodulation level 16 dB below the noise level at the receiver input as an example. If the jammer detector detects the jammers in band A, it is also protected against the jammers in portions of band B as well since IMR3 products are avoided. This jammer detection and protection is due to the intermodulation mitigation for bands A and B. However, in some cases, jammers are present at band B only, or in other cases, jammers are at the higher portion of band B which is not covered by the intermodulation formulation due to the narrow bandwidth limitation of the NB JD. Two cases in band B for jammer detection are: a) when there is no jammer in band A but there is a jammer in a higher frequency portion of band B (where intermodulation is not created by bands A and B); and b) when there is no jammer in band A but there is a jammer within band B that can create intermodulation products with band A. In this latter case, since there is no jammer in band A, there is no jammer protection against the jammer in band B. For this case, there is a need for WB-JD and WB-JD is implemented.
Frequency bands of band C represent the concurrency frequencies such as cellular radio and various other transmit applications such as Global System for Mobile Communications (GSM), wideband code division multiple access (WCDMA), Bluetooth (BT), IEEE 802.11, etc. which cause gain compression, cross-modulation, or intermodulation products over a wide range of band B in UHF. This concurrent frequency transmission may be generated internally by concurrent transmitters or might be received by the antenna (not shown) coupled to the dual mode receiver.
In one example, the jammer detector supports all applicable standards and frequency bands such as: VHF 168 MHz-245 MHz; UHF 470 MHz-750 MHz; L bands that are categorized by two sub-bands, L1 of 1452 MHz-1492 MHz and L2 of 1670 MHz-1675 MHz (USA).
Table 1 illustrates an example of band definitions for defining jammer coverage. As shown in Table 1 an L band system naturally operates within the concurrency domain defined by band C. Additionally band B and band C may create IMR products for instance 2×700 MHz-1400 MHz. Band A is the band edge of the NB JD shown in the radio frequency (RF) band and follows the local oscillator (LO) setting. Band B is defined as the standard band of operation of the receiver and contains band A. LO setting in this example is the lower frequency for each operation band.
Table 2 illustrates an example of definitions for band A, B and C for a multi band receiver such as the dual mode AGC receiver 100. The covered portion of band B against intermodulation products is within LO±36 MHz to LO±72 MHz, since the operational bandwidth of the NB JD is 36 MHz and detection of a jammer by the NB JD protects against intermodulation products. The NB JD protects against intermodulation products for an additional 36 MHz which is LO±72 MHz. However if there are no jammers within the NB JD range of detection, LO±36 MHz, there would be no protection against intermodulation products by the NB JD in the band B range of LO±36 MHz to LO±72 MHz. Since the protection against compression nonlinearities must cover over the entire band B and band C, the jammer detector includes wideband receiver operation by implementing a WB JD as well. LO setting for this example is at any frequency within the relevant band of operation.
In one aspect, a hardware implementation of the jammer detector comprises two components, a NB JD in the analog baseband section and a WB JD in the RF section.
In one example, the NB JD samples the zero intermediate frequency (ZIF) analog baseband signal after the mixer output which can be, for example, a transimpedance amplifier (TIA) prior the ABB LPF 740a, 740b (analog baseband low pass filter). In another example, the analog baseband signal is a non-zero intermediate frequency. In conventional superheterodyne receivers, the NB JD samples the IF signal, prior to the input of the IF bandpass filter (BPF) as an example. The sampled signal is routed to a comparator as depicted by
a illustrates an example of a hardware implementation of a jammer detector comprising a narrowband jammer detector (NB JD) component and one implementation of the wideband jammer detector (WB JD) component. The WB JD protects the receiver from gain compression, cross-modulation due to “far off” jammers with very high protection ratio and intermodulation products. The “far off” jammers cannot be detected by the NB JD because of its bandwidth limitations, for example, 36 MHz. The addition of the WB JD overcomes the bandwidth limitation of the NB JD. Furthermore, the VHF, UHF and L bands are protected for bands A, B and C. The addition of the WB JD solves the coverage problem presented in Table 1. In one example, the WB JD is implemented in hardware and covers band B, and a software jammer detector implementation covers concurrent operation in band C.
In
a illustrates an example implementation for extending detection of jammers within the receiver bandwidth (band B). NB JD detection capability can be extended by increasing the coverage of band B. The implementation shown in
In one example, the jammer detector as shown in
b-9d illustrate examples of receiver implementations in accordance with the present disclosure. In one aspect, the receiver enhances the Mode 2 operation while it is desensitized from concurrent transmitters by incorporating notch filters 940 in the LNA path of Mode 2 as shown in
fABB=5fLO−3fConcurrent
fABB=3fLO−2fConcurrent
In addition, the notch filter 940 mitigates other undesirable effects such as cross-modulation, high third-order intermodulation ratio (IMR3) and gain compression. In one example, the notch filter is tunable at its center frequency to optimize rejection of concurrent transmission leakage. Several notches in the frequency domain can be implemented to reject various concurrent transmitter signals in a MultiCom radio. Alternatively, these notches can be bypassed to improve the frequency response when the receiver operates in Mode 1, as shown in
In another example, the RF notch filters is implemented in the Mode 2 case only. In one example, the notch filters are activated when the SW-JD detects a concurrent transmission activity. In another example, a HW-JD with sufficient bandwidth can detect concurrent transmission activity and activate notch filters. The SW-JD may monitor concurrent transmission on a downlink and decide to activate the notch if a strong interference is received. In one example, the strong interference is defined as interference above a predetermined value. One skilled in the art would understand that the predetermined value may be based on many factors without limiting the scope or spirit of the present disclosure. In another example, the notches may be implemented permanently in Mode 2 without any notification from the SW-JD or WB-JD.
a illustrates an example of interrupt sources and status reporting to a jammer detector register. The NB JD has a limited bandwidth to detect jammers. The WB JD is used as an additional jammer detector to support coverage of bands B and C. In one example, the setting of the thresholds for the NB JD and WB JD can be performed by a single-wire serial interface (SSBI) bus. Interrupts may generate a jammer report for fast attack process. A SSBI status read may generate a jammer detection status for slow release status read during polling as described in
NB JD is a limited bandwidth device to detect jammers up to, for example, a 36 MHz bandwidth. WB JD is used as jammer detector to support coverage of band B. Both jammer detectors report when tripped by a jammer.
a illustrates an example interrupt report and statuses generation from the NB JD and WB JD. As illustrated in the example in
a shows an example of four set reset (SR) flip-flops to store statuses of the JD report of interrupts. The number of flip-flops can be minimized and logic can be modified. The purpose of the flip-flops is to increase flexibility and to provide more debug options for the JD reporting logic. The NB JD produces the NB-JD_INT at the Set (S) input of a dedicated SR FF. The output of that FF is a status named “NB-JD_INT_Status”. This signal comes from the NB JD and is used also to produce an interrupt. This option is useful when operating at a single interrupt source. In the same way the WB JD produces the WB-JD_INT at the Set (S) input of a dedicated SR FF. The output of that FF is a status named “WB-JD_INT_Status”. This signal comes from the WB JD and is used also to produce an interrupt. This option is useful when operating at a single interrupt source. Propagation of both status signals can be blocked individually using an AND gate. NB JD status (“JD1_INT_Status”) is blocked by “Mask NB-JD” and WB JD status is blocked by “Mask-“WB-JD”. The output of the two AND gates is the interrupt signal propagation. The NB JD signal is NB-JD_INT_Out and the WB_JD signal is WB-JD_INT_Out. In case two interrupts mode is enabled, “Two Interrupts” control bit equals “1”, and “WB-JD_INT_Out” is routed to a second SR FF via an additional AND gate. The output of that AND gate in named “JD2_Interrupt” and it feeds the set input of the second dedicated SR-FF. The output of that dedicated FF is the interrupt status of the WB_JD named as “WB-JD_INT_Output_Status” That interrupt status passes an AND gate and becomes an interrupt signal named as “WB-JD_INT_Output” That interrupt is masked individually during a polling process done at release time by a masking control bit named “WB-JD_INT_EN”. The NB JD signal named NB-JD_INT_Out is routed to an OR gate. In case of two interrupt mode, i.e. “Two Interrupts” control bit equals “1”, the second input of the OR gate is “0”. As a consequence, the output of the OR gate named “JD interrupt” that feeds the set input (S) of a dedicated SR FF represents the NB JD interrupt source. The output of that SR FF named “NB-JD_INT_Output_Status” serves as the NB_JD status bit and interrupt source for the NB_JD. The “NB-JD_INT_Output_Status” feeds an AND gate and produces the interrupt signal named “NB-JD_INT_Output” or “JD_Interrupt_Output”. This interrupt signal can be masked individually by the “NB-JD_INT_EN” during a polling process and release time. The “NB-JD_INT_Output_Status” or “JD_INT_Output_Status” signal is used also as the NB JD status bit in a polling process during the release time. The four mask options adds debug options and further resolution for the interrupt source, however those options can be minimized by giving up the two output SR-FFs and two output AND gates to save logic and signals.
When operating at a single interrupt the usage of four SR-FFs saves status readings and provides a choice of what status to be read depending on application. In case a single read is requested, the status of the output SR-FF status named NB-JD_INT_Output_Status is read. If the source of interrupt is requested, NB-JD_INT_Status or WB-JD_INT-Status is read. Having only two SR-FFs, one for each JD, would require reading two JD status bits, one for the NB JD and the other for the WB JD during the polling process occurring at the release time either for a single interrupt configuration or two interrupts configuration.
As an example, to save resets, all SR-FFs are reset by a single control bit named “INT_CLEAR” to clear the interrupt and status bits. The “INT_CLEAR” signal applied on the reset input of the SR-FF has a priority over the set input of the SR-FF. INT_CLEAR is performed by a digital signal processor, general purpose processor or hardware that manages the AGC and JD on the digital baseband side.
In one aspect, an additional set reset flip flop (SR FF) is added to keep the status bit for an interrupt state from the WB JD. In a single interrupt, the two interrupt control bits are “0”. After the interrupt is reset in the wakeup mode, the output of both the status (WB-JD_INT_Output_Status) and interrupt (WB-JD_INT_Output) report of JD2 is at “0” permanently as there is no use for the JD2 interrupt option. In one aspect, it can be programmed for two interrupts. In one aspect, the number of interrupts and statuses are extended to equal the number of jammer detector components (WB JD, NB JD, etc.) that are implemented to increase the resolution and identification of a jamming source. In one example, an interrupt assertion provides a status report to the status register dedicated bit to inform the source of an interrupt event, whether it is a close or a far jammer and the source of detection, either the NB JD or WB JD. The information provided is useful for diagnostics and debugging.
SR FFs (set reset flip-flops) are used to keep the status bit for an interrupt state of WB JD and NB JD. In case of a single interrupt operation mode, WB-JD_INT_Output signal is blocked, but the interrupt source is detected by polling the status bit of the WB JD. The interrupt and status stay high until they are reset to “0” by a processor. Any interrupt assertion provides also a status report to the status register dedicated bit to inform the source of interrupt event, close or far jammer and source of detection NB JD or WB RF detector JD. This is useful for diagnostics and debugging.
In one aspect,
There are two masks for the interrupt, one for NB JD and one for WB JD for the debugging option. When the processor masks the interrupt (NB-JD_INT_Output and WB-JD_INT_Output), the JD_Interrupt_Output_Mask is “0”. The two lines of Mask_WB-JD_INT and Mask_NB-JD_INT are at “1” at all times and are used for debug purposes as an example as shown in
In one aspect, the jammer detector is implemented with other implementations besides a hardware implementation. Listed below are examples of other feasible implementations for performing the functions of the jammer detector in accordance with the present disclosure.
1) hardware
2) modem
3) concurrency
4) sweep mode
One skilled in the art would understand that the jammer detector is not limited to the examples or combinations of the examples listed below, and that other feasible implementations may be used without affecting the spirit and scope of the present disclosure.
In the example in
In another aspect, the jammer detector is implemented in a multi-communication unit (“multicom unit”). In one aspect, a multicom unit includes a receive and transmit platform operable on a variety of applications. One example of a multicom unit is a multicom radio mobile telephone operable on a variety of applications. In another example, a multicom radio mobile telephone has several levels of integration to meet various applications.
In the example shown in
1. High attach rate
2. Medium attach rate
3. Low attach rate
In one aspect, the multicom radio mobile telephone depicted in
One implementation of
b illustrates a hardware JD, including a combination of a NB JD 1380 and WB JD 1390 along with a software JD 1330 to cover concurrent operation. The software JD posts and reports on a bulletin board 1360 a priori concurrent transmit information from cellular sources 1350a (e.g. GSM, WCDMA, LTE, etc.), WiFi 1350b (IEEE802.11), and Bluetooth 1350c, for example. In addition,
In one aspect, the software-based jammer detector 230, 1330 includes a coexistence management unit for monitoring power consumption of a multicom unit wherein the coexistence management unit can optionally provide a power consumption current log. In one aspect, the coexistence management unit manages the operations of a receiver by notifying of expected transmissions or by organizing a silence for the receiver. Also, in one example, the coexistence management unit maps at least one of a spectrum, a RF level or a transmit level based on GPS location. In one example, the software-based jammer detector is a component within the receiver.
In one aspect, the software-based jammer detector selects different mixer types. For example, the different mixer types comprise a single-ended resistive mixer (SRM) and a harmonic reject mixer (HRM). In one example, the different mixer types are within the LNA-Mixer 750 (shown in
In one aspect, the jammer detector is used for power consumption optimization. For example, the following steps illustrate the optimizing of the LNA operating point and biasing based on the jammer detector state:
One skilled in the art would understand that the steps for optimizing LNA operating point and biasing described herewith are not exclusive and that other steps or combinations thereof may be used without affecting the spirit and scope of the present disclosure.
In another example, the following steps illustrate the optimization of the analog baseband (ABB) section filtering:
One skilled in the art would understand that the steps for optimizing the analog baseband (ABB) section filtering described herewith are not exclusive and that other steps or combinations thereof may be used without affecting the spirit and scope of the present disclosure.
In another example, the receiver switches between a regular mixer (SRM) and a harmonic mixer (HRM) based on the jammer detector indication and the type of jammer so as to optimize the mixer type.
c illustrates an example of an interference scenario where concurrent radio systems are operating, and the transmitter from one system couples spurious signals into the receiver of another system. In one example, the SW JD determines ahead of time that the radio operations of the two systems will be concurrent and proactively protects the receiver hardware path. In one aspect, the LNA path is selected as Mode 2 to provide improved linearity. In another aspect, the receiver mixer is switched from a single-ended resistive mixer (SRM) to harmonic reject mixer (HRM) to improve the protection against specific spurious products. For example, the receiver protects against spurious products resulting from the mixing of the third order harmonic of the RF signal with the fifth order harmonic of the local oscillator (LO) signal (i.e. 3RF-5LO product) and from the mixing of the second order harmonic of the RF signal with the third order harmonic of the LO signal (i.e. 2RF-3LO product). This step generally improves the receiver third order intercept point (IP3) and second order intercept point (IP2) to provide better linearity.
In another example, the following steps illustrate the optimization of the mixer bias point:
One skilled in the art would understand that the steps for optimizing the mixer bias point described herewith are not exclusive and that other steps or combinations thereof may be used without affecting the spirit and scope of the present disclosure.
a and 14b illustrate two examples of RF power versus jammer voltage relationship. Shown in
Accordingly, the jammer detector with the divided gain state/adaptive thresholds protects the receiver over the entire power range defined for that gain state, decreases the misdetection probability and maximizes the dwell in the G0 gain state. The divided gain state with the adaptive thresholds increases the receiver sensitivity without causing susceptibility to jammer distortion and C/N degradation. Usage of adaptive thresholds relaxes the G0 gain state requirements since the reference level for detection in point A in
In one aspect the wideband threshold is adaptive based on wanted power. In another aspect, the narrowband threshold is adaptive based on wanted power. In one example the wideband threshold or the narrowband threshold is loaded by an automatic threshold setting logic (not shown), wherein the automatic threshold setting logic is optionally based on the gain state of a radio frequency integrated circuit (RFIC).
In another aspect, the WB JD and NB JD components are implemented using existing hardware designs. In one example, the NB JD decision logic is used as a digital low pass filter to create easily programmable conditions for identifying jammers, for example, for N±1 to N±4. The decision logic of the NB JD is used for both wideband and narrowband jammer detection. The NB JD decision logic estimates jammers by integrating within a predefined gate of a number of crystal oscillator cycles. This process defines the pass/fail threshold. In one example, the pass/fail threshold is digital and programmable.
In one aspect, the WD JD is based on a RF detection (self mixing, RF detector, etc.) of received energy. The WD JD reports a voltage proportional to the wideband jammer duration. For example, integration of the WB JD with the NB JD is based on the following considerations:
The power saving process can be implemented on several receivers which are sharing the same source of JD information about a concurrent transmit activity or transmitting termination. That approach of concurrent activity JD information sharing is one aspect of horizontal integration approach suggested in our invention.
In one example, the receiver includes a functionality to ignore the jammer detector interrupt and to mask the jammer detector interrupt automatically based on a predetermined gain state. The receiver logic block will identify the predetermined gain state and will implement an automatic mask for that predetermined gain state and any gain state above it. An actual gain state of the receiver is obtained by reading the gain state command from the AGC circuit, logic or algorithm that is sent to the receiver logic block. In one aspect, there are two ways to ignore the jammer detector interrupt: 1) automatically mask the jammer detector interrupt bit for gain states that are predetermined to be masked and 2) reset the jammer detector interrupt bit and maintain it at a value of zero. In one aspect, the gain states that are predetermined to be masked are programmable. The automatic masking can be activated or deactivated, for example, by a command from the receiver RF section, by a command from a processing unit associated with the receiver or by a command sent through a single-wire serial bus interface (SSBI) or any other interface. In another aspect, the mask to the jammer detector interrupt is removed by a processing unit associated with the receiver in either the automatic masking or regular operation. Additionally, the interrupt masking can be further expanded to turn off the jammer detector hardware and save energy while the receiver is in gain states that are not relevant for jammer detection operation. In one aspect, reactivation of the jammer detector is automatic if the gain state is one level higher than the predetermined gain state. JD refers to either in mode 1 or mode 2.
In one aspect, the receiver incorporates the functionality for loading jammer detection thresholds based on the assertion interrupt and gain states. The gain states are obtained by reading the gain state command from the AGC circuit sent to the receiver logic block. If the gain state directs the receiver to change to a gain state in which the jammer detector is valid and the interrupt is set to “1”, the receiver logic block will automatically set the jammer detection thresholds based on the gain state and interrupt state being equal to “1”, i.e. jammer was detected. If the gain state is outside the jammer detection activity and therefore is ignored, the receiver logic block will not perform automatic updating. Where there is an automatic mask of the jammer detector interrupt, the receiver logic block will block the jammer detector interrupt. In one example, the thresholds loadings are part of a polling process and a slow release algorithm. As an example, when receiver is at mode-2 (high-linearity moderate sensitivity), its JD has a threshold for mode 2 where the threshold is determined based on gain state. A threshold for mode 1 (high sensitivity low NF) is loaded by a management entity, such as a processor, only if at the end of the polling process of JD interrupt status bit (which lasts during the release time) all JD status bits that were read showed “0”. The JD threshold levels are loaded based upon gain state when going from mode 2 to mode 1.
In one aspect, a multicom unit includes a variety of transceivers and companion receivers to provide a variety of simultaneous applications, services and connectivity abilities. In concurrent operation, the sensitivity of a receiver that is used for one application may be affected by the simultaneous transmission from a transmitter used for another application, due to the small size and high level of integration and finite isolation as illustrated in Table 3. The receiver and interfering transmitter combinations are elaborated in Table 4 as an example.
The radio types within the multicom unit operate over a wide bandwidth as an example from 168 MHz up to 2.7 GHz or, in another example, up to 5 GHz. In this particular case, a hardware based JD solution to enable concurrent operation is not practical. To mitigate the input power range over which the interfering signal is received, a very wideband and high dynamic range detector of approximately 70 dB is required. Table 5 summarizes an example of universal broadcast modem (UBM) digital TV receiver requirements for enabling concurrent operation with other co-resident radio types. Table 5 represents typical interference effects on performance which are applicable to any type of radio receiver.
The UBM receiver is susceptible to the following interference types due to concurrent operation with other transmitters:
Table 4 illustrates that the high linearity performance enables the receiver to mitigate the effects of strong interfering signals while other transmitters are being used. One way to mitigate strong interference, for example, is by notifying the relevant receivers that a specific concurrent transmitter at a specific frequency is activated and that its power level exceeds a predefined threshold. The notification can be utilized by the receiver to enhance linearity, or to change its operation mode (for example, from a high sensitivity mode to a high linearity mode) and thus protect the receiver sensitivity in the presence of concurrent jammers. If no notification is provided to the receiver, i.e. there is no concurrent transmission or the transmission is below a predetermined threshold, other receiver parameters such as sensitivity and power consumption can be optimized. The notification approach allows optimization of key receiver parameters according to the jammer environment and therefore provides improvement on overall performance as elaborated by Table 4. In one example, the notification is generated by a central software based mechanism that coordinates the operation of all the transceivers. In another example, all receivers can be notified of concurrent operation and can undertake protective actions to avoid desensitization as elaborated by Table 6. The same protective mode is activated by both the narrowband and wideband jammer detectors.
In a parallel path, from block 1700, proceed to block 1705. In block 1705, downconvert the input signal to generate a downconverted input signal. Following block 1705, proceed to block 1715. In block 1715, sample the downconverted input signal to generate a sampled downconverted (SD) input signal. In block 1725, compare the SD input signal with a narrowband jammer threshold THNB and proceed to block 1735. One skilled in the art would recognize that the value of THNB can be based on various factors, such as but not limited to, system application, design constraints and/or user choice without affecting the spirit and scope of the present disclosure. In one example, the values of THNB are stored in a memory. In block 1735, generate a narrowband interrupt signal (a.k.a. NB interrupt signal) based on the narrowband (NB) comparison results from block 1725. In one example, the NB interrupt signal is a bit. In one example, narrowband is defined as within the bandwidth of a receiver receiving the input signal. Following block 1735, proceed to block 1740.
In block 1740, process one or more of the WB JD interrupt signal or NB JD interrupt signal to generate a processing result and proceed to block 1750. In one example, the processing result is an indicator of whether one or more of the WB JD interrupt signal or NB JD interrupt signal include a bit to indicate the presence of a jammer. In one example, the processing result is a bit. In block 1750, generate a composite interrupt signal based on the processing result and proceed to block 1760. In one example, the composite interrupt signal is an indicator of whether or not a jammer has been detected. In one example, the composite interrupt signal is a bit. In one example, an interrupt logic module (e.g., a logic circuit) within the jammer detector generates the composite interrupt signal based on the processing result. In block 1760, evaluate the composite interrupt signal to determine if a jammer is present. In one aspect, the evaluating step evaluates the bit value of the composite interrupt signal to determine if a jammer is present. In one example, the AGC circuit performs the evaluating step. In one aspect, following block 1760, in block 1770, a receiver mode is selected based on the presence of the jammer.
In one aspect, the flow diagram of
One skilled in the art would understand that the jammer detector as disclosed in the present disclosure can be used with any type of receiver design, including a dual mode receiver, without affecting the spirit or scope of the present disclosure.
Those of skill would appreciate that the various illustrative components, logical blocks, modules, circuits, and/or algorithm steps described in connection with the examples disclosed herein may be implemented as electronic hardware, firmware, computer software, or combinations thereof. To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and/or algorithm steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope or spirit of the present disclosure.
For example, for a hardware implementation, the processor(s) may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described therein, or a combination thereof. With software, the implementation may be through modules (e.g., procedures, functions, etc.) that perform the functions described therein. The software codes may be stored in memory units and executed by a processor. Additionally, the various illustrative flow diagrams, logical blocks, modules and/or algorithm steps described herein may also be coded as computer-readable instructions carried on any computer-readable medium known in the art.
In one or more examples, the steps or functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.
In one example, the illustrative components, flow diagrams, logical blocks, modules and/or algorithm steps described herein are implemented or performed with one or more processors. In one aspect, a processor is coupled with a memory which stores data, metadata, program instructions, etc. to be executed by the processor for implementing or performing the various flow diagrams, logical blocks and/or modules described herein.
The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the spirit or scope of the disclosure.
The present Application for Patent claims priority to Provisional Application No. 61/085,325 entitled Method and Apparatus for Providing Jammer Detection In A Receiver filed Jul. 31, 2008, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.
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