CN106508112B - Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tate - Google Patents
Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tateInfo
- Publication number
- CN106508112B CN106508112B CN201010049159.4A CN201010049159A CN106508112B CN 106508112 B CN106508112 B CN 106508112B CN 201010049159 A CN201010049159 A CN 201010049159A CN 106508112 B CN106508112 B CN 106508112B
- Authority
- CN
- China
- Prior art keywords
- frequency
- mode
- node
- transmission
- data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Abstract
The invention discloses the auto-adaptive parameter system of selection in a kind of multi-mode multi tate cognitive radio system, the method includes the spectrum information perceived by interaction receiving-transmitting sides, execute adaptive algorithm, optimal physical layer communication parameter is selected, to improve the reliability of the capacity of wireless cognition network, the utilization rate of frequency spectrum and communication.The inventive method needs communication node carry out real-time perception to channel around, has taken into full account the multiformity of node surrounding environment change, and can be reasonably resistant to channel high progression and bursty interference, mitigates impact of the emergency case to systematic function.The inventive method neatly can be selected optimum physical layer parameter, can meet the transmission of multiple QoS business according to the transmission success rate required by upper-layer service data and threshold bit error rate using flexibly adaptively selected strategy.
Description
Technical field
The present invention relates in wireless communication technology field, more particularly to multi-mode multi tate cognitive radio system
Auto-adaptive parameter system of selection.
Background technology
With the fast development of radio communication, due to some characteristics of radio communication itself, such as mobility, letter
Road condition changes frequent etc., and existing communication system is faced with two crucial challenges always.
First：How real-time adaptive frequently changes communication system in channel around.If wireless network
Middle speed and frequency range using fixation, it is impossible to which adaptive channel changes and adjusted, cannot ensure that data are passed
Defeated success rate and the availability of frequency spectrum.Communication node is accomplished by possessing and the channel of itself can be perceived in real time
Ability, and can according to local channel situation, carry out available bandwidth and communication frequency selection.
Second：How communication node is adaptive to change of the different business for QoS.Communication node is needed
Data transfer is realized using the modulation technique of different qualities according to the qos requirement of upper-layer service.Such as,
For closely indoor broadband radio communication, because multipath fading is serious, and in order to obtain higher transmission
Speed, is a kind of effective solution using OFDM modulation technology；And in satellite communication system
In, in order to obtain higher power efficiency and farther transmission range, more use MPSK or CPFSK are permanent
Envelope modulation.
In order to cater to the demand, communication system must possess perception, study and the ability for adapting to change, energy
Channel circumstance around real-time perception, and transport parameters for physical layer can be changed to adapt to the change of environment, and it is cognitive
The technology platform that radio (Cognitive Radio, CR) technology undoubtedly provides the foundation.
How communication system is according to different business qos requirement and communication channel situation, to select best transmission to join
Number, so as to lift the overall performance of network, including the index such as the bit error rate, transmission success rate and the availability of frequency spectrum,
This is also one of important directions of cognitive radio research in recent years.
In the adaptive algorithm of current cognitive radio, only considered under same modulation system mostly,
The different mapping mode of selection, to meet the requirement of the QoS bit error rates.In order to allow the communication system can be a variety of
Under channel condition, including broadband awgn channel, frequency selective fading channels, high-speed mobile/strong Doppler
Frequency displacement, can be adaptive selected optimal modulating mode and carry out data transmission, the excursion of available bandwidth
Can be from 50kbps to 2Mbps, if simply using a kind of modulation system, it is clear that can not reach well
Laser propagation effect.
The content of the invention
In view of the above-mentioned deficiencies in the prior art, it is an object of the present invention to provide multi-mode multi tate cognitive radio system
Auto-adaptive parameter system of selection in system.
The present invention is achieved through the following technical solutions, the self adaptation ginseng in multi-mode multi tate cognitive radio system
Number system of selection, comprises the following steps：
1st, node carries out frequency spectrum perception, generates locally available frequency spectrum report.Specific method is：In idle condition,
The link layer protocol of node indicates that physical layer carries out frequency spectrum perception with certain cycle, and link layer obtains physical layer
The result of frequency spectrum perception, and generate node frequency spectrum perception report.
2nd, sending node request data transmission before, need to be sent on control channel Fc the usable spectrum of oneself to
Receiving node.Specific method is：When sending node TS needs to send data to recipient node RS, first
The frequency range claim frame FSR (Frequency Spectrum Report) of current spectral perception report will be contained,
RS is sent on control channel Fc by the way of competition, attempts and RS sets up connection.Sending FSR
A period of time in, if TS does not receive the response TPA of other side also, by assert this time attempt fail,
The mode of random back is taken, trial next time is carried out.It is more than threshold values Fth when attempting the frequency of failure, it is believed that
Connection sets up failure and notifies upper strata.
3rd, receiving node is according to other side and the usable spectrum situation of oneself, and selection is this time transmitted frequency Fs and obtained
To available bandwidth B.Specific method is：System channel total bandwidth Bw is divided into K frequency range, the spacer step of frequency range
Enter for Fstep=Bw/K, the form that frequency spectrum perception is reported is the 0-1 sequences of K points, and ' 0 ' represents the frequency can
With ' 1 ' to represent the frequency occupied；RS receive from TS frequency spectrum perception report FSR, and by this two
Individual K point sequences carry out intersection operation, obtain available frequency point sequence Sa；In available frequency point sequence Sa, search
Rope most long continuously available frequency range, and obtain its starting and with frequency Fb and can terminate that frequency Fe can be used, obtain
Available bandwidth B=Fstep* (Fe-Fb), centre frequency Fs=(Fe+Fb)/2.According to Qos grades of business
Huo get not threshold bit error rate Peth and FER thresholding Pbth.According to Qos ranks, acquisition current business of tabling look-up
Required threshold bit error rate Peth；According to formula Pbth=1- (1-Peth)l, l is data packet length, obtains frame by mistake
Rate Pbth.
4th, receiving node performs adaptive algorithm according to available bandwidth B and qos requirement, and selection is this time transmitted
Parameter (modulating mode m and mapping mode p), and inform sending node.Specific method is：
(1) modulating mode m is selected, the M kind modulating modes supported in equipment, what every kind of modulating mode took
Bandwidth is different from.bmBandwidth is divided into M misaligned intervals, interval border isWhen
Available bandwidth B ∈ [bm, bm+1), m=1 ... during M, selects modulating mode m.
(2) according to the bit error rate and the derivation formula of signal to noise ratio and Peth under different mappings mode, mapping is calculated
The value γ of minimum signal to noise ratio under mode nn.SNR is divided into N number of misaligned interval, interval border isAs signal to noise ratio γ ∈ [γn, γn+1), n=1 ... during N, selects modulating mode n.
5th, sending node sends business datum, and the ACK situations of other side's loopback are counted, and according to ACK
The decision-making of reception result with the presence or absence of disturbing and re-start perception.
(1) sequence number included for ACK frames, is always the data frame number that RS ends are reached recently.When
The ACK sequence numbers that RS is received are less than the data frame number of this transmission, then expression is this time transmitted without success,
TS ends will resend this data frame.TS counts the reception condition to ACK, sends DATA's
Number of times is Td, and the number of times for being properly received feeding back ACK is Ra, obtains transmission success rate for Ra/Td.
(2) the signal-to-noise ratio (SNR) estimation value included for ACK frames, is to channel SNRs when receiving data last time
Estimation.TS counts the situation to SNR, calculates SNR average values γ in a period of time recentlya。
(3) when the probability of success of transmission is less than thresholding (1-Pbth) or γa＜ γnWhen, TS will send termination
Frame TEL is connected, represents that channel has occurred and that change, both sides reselect transmission again after needing channel perception again
Parameter.
The beneficial effects of the invention are as follows,
1st, this method can around real-time perception channel situation of change, select optimal according to adaptive algorithm
The parameter such as physical layer modulation pattern and speed, with improve the capacity of wireless cognition network, the utilization rate of frequency spectrum and
The reliability of communication.
2nd, the inventive method need communication node can to channel around carry out real-time perception, take into full account section
The diversity of point surrounding environment change, and channel high progression and bursty interference can be reasonably resistant to, subtract
Light influence of the emergency case to systematic function.
3rd, the inventive method, can be according to required by upper-layer service data using flexible adaptively selected strategy
Transmission success rate and threshold bit error rate, neatly select optimum physical layer parameter, a variety of QoS can be met
The transmission of business.
Brief description of the drawings
Fig. 1 is communication protocol flow figure of the invention；
Fig. 2 is the sender of the present invention and the workflow diagram of recipient；
Fig. 3 is the determination process of the configured transmission of the present invention；
Fig. 4 is the corresponding relation that type of service of the present invention and the bit error rate tolerate thresholding.
Embodiment
The present invention is described in detail below in conjunction with the instantiation of the data communication flow of receiving-transmitting sides.
It refer to shown in Fig. 1, this is the data interaction flow chart of the system.Transmitting terminal RS and receiving terminal TS
Interaction flow, including perception stage sets up the transmission stage of access phase and data.Specific steps are such as
Under：
(1) after node electrification, into idle condition, channel is perceived by the cycle of T, frequency spectrum is generated
Perceive report.When sending node TS needs to send data to recipient node RS, current spectral will be contained
The frequency range claim frame FSR (Frequency Spectrum Repon) of report is perceived, is sent on control channel fc
To RS, attempt and RS sets up connection.
(2) RS selects suitable modulating mode and mapping mode and available according to the channel-aware situation of both sides
Frequency range, and the result of decision-making is passed through into configured transmission acknowledgement frame TPA (Transmission Parameters Answer)
Pass to TS.
(3) TS is received after configured transmission acknowledgement frame TPA, is configured physical layer relevant communication parameter, is switched to phase
The idle frequency range Fs answered, and connection request RTS (Ready to Send) is sent, confirm both sides all in corresponding
Frequency range, and inform that this time connection needs the information such as data length, time sent.
(4) RS is received after request of data frame RTS, response data request-reply frame CTS (Clear to Send),
Connection is represented it has been established that and entrance receives data mode.
(5) after connection is set up, TS starts to send data frame DATA, when RS often receives a frame data, will send out
Send acknowledgement frame ACK inform reception condition wherein ACK contain receive data frame sequence number and this time
The SNR estimates of transmission；TS is according to ACK content and reception ACK statistical conditions, it is determined whether need
Want retransmission data and whether need to reappraise channel.
(6) TS has been sent after the data once connected, will send connection abort frame TEL (Terminate
Established Link) inform that RS data are sent, both sides are switched to common frequency band Fc and returned to initial
Idle condition.
Shown in reference picture 2, this is the flow chart of the receiving-transmitting sides work of the system.
For transmitting terminal TS, frequency spectrum perception is carried out first, updates local usable spectrum report, and check hair
Whether send queue is empty.If transmit queue has data to need transmission, TS sends FSR to receiving node RS,
The spread spectrum scenarios of oneself are informed, and the TPS data frames for waiting RS to feed back.After TPS is received, according to
Its content, the related messaging parameter of configuration physical layer, including transmission frequency Fs, modulating mode and mapping mode.
After the completion of configuration, TS sends RTS on frequency Fs to other side, informs the length of this time data of transmission, and
The CTS for waiting other side to return.Receive after CTS, take Data Concurrent to give other side from transmit queue, and
Wait the ACK of other side's feedback.If the sequence number and the sequence of transmission data that are included in the ACK frames received
It is number consistent, then show this transmission success, then continuation is fetched evidence from transmit queue, it is known that send team
Untill being classified as sky；Otherwise this bust this is represented, then continue to send the data, be successfully until sending
Only.TS can count the reception condition and SNR average value of ACK in a period of time, send DATA time
Number is Td, and the number of times for being properly received feeding back ACK is Ra, as transmission success rate Ra/Td ＜ (1-Pbth)
Or SNR average values γa＜ γnWhen, represent that channel conditions have occurred and that large change, both sides need again
Channel is estimated and configured transmission is reselected, link abort frame TEL can be now sent to other side.When
TS transmit queues are space-time, represent that this data is sent, and TS sends link abort frame TEL, to inform
Other side is this time transmitted and finished.
For receiving terminal RS, frequency spectrum perception is carried out at one's leisure, when receiving the FSR from transmitting terminal TS,
With reference to oneself local frequency spectrum report, available bandwidth B and selection transmission frequency Fs is obtained.According to available bandwidth
B, selects modulating mode m, the bit error rate of estimation and upper-layer service requirement further according to signal to noise ratio snr,
Choose for user mode n, is this time transmitted used physical layer configuration parameter, and sends TPA and inform TS.
When receiving RTS on frequency Fs, the preparation for receiving data is carried out, and sends CTS, represents that other side can be with
Send data.When receiving data frame DATA, by the sequence number of the secondary DATA frames being properly received and SNR
Estimate, TS is fed back to by ACK frames, informs that this data has been properly received.TEL is terminated when receiving connection
Frame, represents that this time transmission has been finished, terminates to receive and be switched to common signal channel Fc.
Shown in reference picture 3, this is the selection flow of receiving terminal RS messaging parameters in the system.
Available bandwidth B and transmission frequency Fs, system channel total bandwidth Bw is selected to be divided into K frequency range, frequency range
Between stepping be Fstep=Bw/K, frequency spectrum perception report form be K points 0-1 sequences, ' 0 ' represent should
Frequency can use, and ' 1 ' to represent the frequency occupied；RS receives the frequency spectrum perception report FSR from TS, and
The two K point sequences are subjected to intersection operation, available frequency point sequence Sa is obtained；In available frequency point sequence Sa
In, frequency Fe can be used with frequency Fb and end by searching for most long continuously available frequency range, and obtaining its starting,
Obtain available bandwidth B=Fstep* (Fe-Fb), centre frequency Fs=(Fe+Fb)/2.According to Qos grades
Not, the threshold bit error rate Peth tabled look-up required by acquisition current business；According to formula
Pbth=1- (1-Peth)l, l is data packet length, obtains FER Pbth.
Modulating mode m is selected, the M kind modulating modes supported in equipment, the bandwidth that every kind of modulating mode takes
It is different from.bmBandwidth is divided into M misaligned intervals, interval border isWhen available
Bandwidth B ∈ [bm, bm+1), m=1 ... during M, selects modulating mode m.
According to current type of service, the tolerance thresholding Peth of the bit error rate under the business is obtained.Further according to difference
The derivation formula and Peth of the bit error rate and signal to noise ratio under mapping mode, calculate minimum letter under mapping mode n
Make an uproar than value γn.SNR is divided into N number of misaligned interval, interval border isWork as signal to noise ratio
γ∈[γn, γn+1), n=1 ... during N, selects modulating mode n.
Shown in reference picture 4, this is the corresponding relation of the tolerance thresholding of type of service and the bit error rate in the system.
For the type of service on the upper strata in system, the tolerance thresholding of the bit error rate can be selected according to the form
Peth, and then obtain optimal messaging parameter.
Presently preferred embodiments of the present invention is the foregoing is only, is not intended to limit the invention, it is all in this hair
Within bright spirit and principle, any modifications, equivalent substitutions and improvements made etc. should be included in this hair
Within bright protection domain.
Claims (4)
1. a kind of auto-adaptive parameter system of selection in multi-mode multi tate cognitive radio system, its feature exists
In this method comprises the following steps：
(1) node carries out frequency spectrum perception, generates locally available frequency spectrum report；
(2) when node has data to send, the node needs and recipient sets up connection：It is public in network
Control channel Fc on send usable spectrum report FSR to receiving node, and include this transmission upper-layer service
Qos ranks；
(3) receiving node carries out intersection operation, choosing according to the set of sender and the usable spectrum of itself
Select the frequency Fs and available bandwidth B of this time transmission；
(4) receiving node performs adaptive algorithm according to available bandwidth B and QoS level, and selection is this time passed
Defeated parameter, and sending node is informed, the configured transmission includes modulating mode m and mapping mode n；
(5) sending node sends business datum, and the ACK situations for having correctly received other side's feedback are united
Meter, and decide whether to have interference according to ACK reception result and re-start perception；
The step (3) is specially：
(3.1) frequency Fs and available bandwidth B selection；System channel total bandwidth Bw is divided into K frequency range,
Stepping is Fstep=Bw/K between frequency range, and the form of frequency spectrum perception report is the 0-1 sequences of K points, ' 0 '
Represent the frequency can use, ' 1 ' to represent the frequency occupied；RS receives the usable spectrum report FSR from TS,
And the two K point sequences are subjected to intersection operation, obtain available frequency point sequence Sa；In available frequency point sequence Sa
In, frequency Fe can be used with frequency Fb and end by searching for most long continuously available frequency range, and obtaining its starting,
Obtain available bandwidth B=Fstep* (Fe-Fb), frequency Fs=(Fe+Fb)/2；
(3.2) threshold bit error rate Peth and FER thresholding Pbth is obtained according to business Qos ranks；Root first
According to Qos ranks, table look-up the threshold bit error rate Peth obtained required by current business；According to formula
Pbth=1- (1-Peth)l, l is the length of data block, obtains FER Pbth；
The step (4) is specially：
(4.1) modulating mode m is selected, the M kind modulating modes supported in equipment, every kind of modulating mode takes
Bandwidth be different from；bmBandwidth is divided into M misaligned intervals, interval border is
As available bandwidth B ∈ [bm, bm+1), during m=1 ..., M, select modulating mode m；
(4.2) according to the bit error rate and the derivation formula of signal to noise ratio and threshold bit error rate under different mappings mode
Peth, calculates the value γ of minimum signal to noise ratio under mapping mode nn；SNR is divided into N number of misaligned interval,
Interval border isAs signal to noise ratio γ ∈ [γn, γn+1), during n=1 ..., N, Choose for user mode n.
2. the auto-adaptive parameter selection in multi-mode multi tate cognitive radio system as claimed in claim 1
Method, it is characterised in that the step (1) is specially：In idle condition, the link layer protocol of node with
Certain cycle indicates that physical layer carries out frequency spectrum perception, and link layer obtains the result of physical layer frequency spectrum perception, and
Generate node usable spectrum report.
3. the auto-adaptive parameter selection in multi-mode multi tate cognitive radio system as claimed in claim 1
Method, it is characterised in that the step (2) is specially：When sending node TS is needed to receiving node RS
When sending data, the frequency range claim frame of currently available frequency spectrum report will be contained first, on control channel Fc
RS is sent to by the way of competition, attempts and RS sets up connection；Sending in FSR a period of time,
If TS does not receive the response TPA of other side also, it will assert and this time attempt to fail, take random back
Mode, carries out trial next time；It is more than threshold values Fth when attempting the frequency of failure, it is believed that connection sets up failure simultaneously
Notify upper strata.
4. the auto-adaptive parameter selection in multi-mode multi tate cognitive radio system as claimed in claim 1
Method, it is characterised in that the step (5) is specially：
(5.1) sequence number included for ACK frames, is always the data frame number that RS ends are reached recently；
When the RS ACK sequence numbers received are less than the data frame number of this transmission, then expression is this time transmitted without into
Work(, TS ends will resend this data frame；TS counts the reception condition to ACK, sends DATA
Number of times be Td, the number of times for being properly received feeding back ACK is Ra, obtains transmission success rate for Ra/Td；
(5.2) the signal-to-noise ratio (SNR) estimation value included for ACK frames, is to channel noise when receiving data last time
The estimation of ratio；TS counts the situation to SNR, calculates SNR average values γ in a period of time recentlya；
(5.3) when the probability of success of transmission is less than thresholding (1-Pbth) or γa＜ γnWhen, TS will send termination
Frame TEL is connected, represents that channel has occurred and that change, both sides reselect transmission again after needing channel perception again
Parameter, Pbth is FER thresholding, γnFor the value of minimum signal to noise ratio under mapping mode n.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010049159.4A CN106508112B (en) | 2010-07-09 | 2010-07-09 | Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010049159.4A CN106508112B (en) | 2010-07-09 | 2010-07-09 | Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106508112B true CN106508112B (en) | 2014-06-18 |
Family
ID=58335154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010049159.4A Expired - Fee Related CN106508112B (en) | 2010-07-09 | 2010-07-09 | Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106508112B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107040485A (en) * | 2017-04-18 | 2017-08-11 | 西南科技大学 | Adaptive communications receive host computer and slave computer |
| CN111641453A (en) * | 2020-06-08 | 2020-09-08 | 西安电子科技大学 | Adaptive protocol selection method based on serial relay free space optical communication system |
-
2010
- 2010-07-09 CN CN201010049159.4A patent/CN106508112B/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107040485A (en) * | 2017-04-18 | 2017-08-11 | 西南科技大学 | Adaptive communications receive host computer and slave computer |
| CN111641453A (en) * | 2020-06-08 | 2020-09-08 | 西安电子科技大学 | Adaptive protocol selection method based on serial relay free space optical communication system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8320382B2 (en) | Mobile communication system, a mobile station, a base station and communication control method | |
| KR101930332B1 (en) | Method and apparatus for controlling transmit power | |
| JP6422903B2 (en) | Wireless communication apparatus and wireless communication method | |
| JP5639470B2 (en) | Improved multi-user transmission | |
| CN105122890B (en) | Control terminal, base station and the correlation technique of the cell connection from WLAN | |
| CN103379651B (en) | The method and apparatus of transmission signal | |
| CN104393969B (en) | Allow the method and device for using HARQ for the uplink of received in wireless communications | |
| US9768992B2 (en) | System and method for randomized antenna allocation in asynchronous MIMO multi-hop networks | |
| Nguyen et al. | A practical approach to rate adaptation for multi-antenna systems | |
| CN103081542A (en) | Method and apparatus for transmitting and receiving uplink data in mobile communication system | |
| CN113163357B (en) | Method and apparatus in a node used for wireless communication | |
| WO2019119479A1 (en) | Method and apparatus used for wireless communication in user equipment and base station | |
| CN112350806A (en) | Method and apparatus in a node used for wireless communication | |
| CN107925514A (en) | Use the wireless communications method and wireless communication terminal of triggering information | |
| JP2022532878A (en) | Systems and methods for displaying the capabilities of wireless receiving stations | |
| CN108400842A (en) | A kind of state report sending method and device applied to recipient | |
| CN101904195B (en) | Method and apparatus for improving the performance of erasure sequence detection | |
| CN111615213B (en) | Method and apparatus in a node used for wireless communication | |
| CN106508112B (en) | Auto-adaptive parameter system of selection in the cognitive radio system of multi-mode multi tate | |
| JP2017168995A (en) | Wireless communication device and wireless communication method | |
| JP4312792B2 (en) | RECEIVING DEVICE, COMMUNICATION SYSTEM, COMMUNICATION METHOD, COMMUNICATION PROGRAM, AND COMPUTER-READABLE RECORDING MEDIUM CONTAINING THE SAME | |
| CN105187108B (en) | A kind of distributing antenna system cross-layer design method based on link circuit self-adapting | |
| Casari et al. | DSMA: an access method for MIMO ad hoc networks based on distributed scheduling | |
| US9839052B2 (en) | Method for adapting a link for selecting a frame transmission mode and corresponding WI-FI access point | |
| Wang et al. | Joint rate and power adaptation for wireless local area networks in generalized Nakagami fading channels |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR03 | Grant of secret patent right | ||
| GRSP | Grant of secret patent right | ||
| DC01 | Secret patent status has been lifted | ||
| DCSP | Declassification of secret patent | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140618 |