SHORT-DISTANCE CONTACTLESS COMMUNICATION APPARATUS AND METHOD THEREOF
A short-distance contactless communication apparatus includes: a receiver configured to operate under at least a first receiving mode and a second receiving mode, wherein the receiver receives a modulation signal with a first modulation scheme when the receiver is configured to operate under the first receiving mode, and the receiver receives a modulation signal with a second modulation scheme when the receiver is configured to operate under the second receiving mode, and wherein the receiver utilizes an oscillation signal to receive the modulation signal, and the oscillation signal utilized by the receiver is derived from the modulation signal or derived from a reference clock of a local source based on the receiving mode of the receiver.
This application claims the benefit of U.S. Provisional Application No. 61/873,442, which was filed on 2013 Sep. 4 and is included herein by reference.
BACKGROUNDThe present invention relates to a short-distance contactless communication apparatus and method thereof, and more particularly to a short-distance contactless communication apparatus capable of adjusting the envelope of a receiving modulation signal, and method thereof.
Short-range, standards-based contactless connectivity technology such as Near field communication (NFC) uses magnetic field induction to enable communication between electronic devices inclose proximity. Based on RFID technology, NFC provides a medium for the identification protocols that validates secure data transfer. Conventionally, a NFC device encompasses a PCD (Proximity Coupling Device) transceiver and a PICC (Proximity Inductively Coupled Card) receiver. When the NFC device is configured as an initiator (i.e. the PCD mode), the transmitter in the PCD transceiver is used to emit a modulation signal to another NFC device, i.e. the target NFC device. Meanwhile, the receiver in the PCD transceiver receives the emitted modulation signal as an in-band blocking signal or an in-band blocker. Upon detecting the modulation signal transmitted from the transmitter of the PCD transceiver, the target NFC device responds with a load modulation (LM) signal to the receiver of the PCD transceiver. On the other hand, when the NFC device is configured as a PICC target (i.e. the PICC mode), the PICC receiver receives a modulation signal transmitted from another PCD device (i.e. the initiator). Therefore, no matter the NFC device is configured as PCD mode or PICC mode, the NFC device always needs to receive a modulation signal. However, the voltage swing or the power of the modulation signal is depended on the relative position between the two NFC devices, and the matching network and the antenna coils of the two NFC devices. If the voltage swing or the power of the modulation signal is too large, it may exceed the dynamic range of the receiver of the NFC device. If the voltage swing or the power of the modulation signal is too small, the modulation signal may not be accurately demodulated by the NFC device. Therefore, providing an NFC device capable of accurately receiving the modulation signal during the PCD mode and the PICC mode is an urgent problem in the NFC field.
SUMMARYOne of the objectives of the present invention is to provide a short-distance contactless communication apparatus capable of adjusting the envelope of a receiving modulation signal, and method thereof.
According to a first embodiment of the present invention, a short-distance contactless communication apparatus is disclosed. The short-distance contactless communication apparatus comprises a receiver configured to operate under at least a first receiving mode and a second receiving mode, wherein the receiver receives a modulation signal with a first modulation scheme when the receiver is configured to operate under the first receiving mode, and the receiver receives a modulation signal with a second modulation scheme when the receiver is configured to operate under the second receiving mode. The receiver utilizes an oscillation signal to receive the modulation signal, and the oscillation signal utilized by the receiver is derived from the modulation signal or derived from a reference clock of a local source based on the receiving mode of the receiver.
According to a second embodiment of the present invention, a short-distance contactless communication apparatus is disclosed. The short-distance contactless communication apparatus comprises a receiver capable of operating under a proximity coupling mode and/or a proximity inductively coupled card mode and an adjusting device. The receiver is coupled to a signal receiving port of the short-distance contactless communication apparatus. The adjusting device is coupled to the signal receiving port for adjusting a peak voltage level of a modulation signal on the signal receiving port to fall within a predetermined voltage range.
According to a third embodiment of the present invention, a short-distance contactless communication method is disclosed. The short-distance contactless communication method comprises the steps of: using a receiver capable of operating under a proximity coupling device (PCD) mode and/or a proximity inductively coupled card (PICC) mode to couple to a signal receiving port; and adjusting a peak voltage level of a modulation signal on the signal receiving port to fall within a predetermined voltage range.
According to a fourth embodiment of the present invention, a NFC device comprising an NFC integrated circuit (IC) capable of supporting PCD and PICC reception is disclosed. The NFC device comprises PCD and PICC receivers have a common input port, a fixed resistor coupled to the common input port, an envelope detector coupled to the common input port, a programmable resistor circuit having a first node coupled to the common input port and a second node coupled to ground. The resistance of the programmable resistor circuit is adjusted according to the peak voltage level at the input of the envelope detector, and the adjustment of the programmable resistor circuit continues until the peak voltage at the input of the envelope detector is within a predetermined voltage range.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, electronic equipment manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. Also, the term “couple” is intended to mean either an indirect or direct electrical connection. Accordingly, if one device is coupled to another device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
Please refer to
In this embodiment, the NFC integrated circuit 102 is a single-chip. The EMI low-pass filter 104, the matching network 106, the phase shifting network 108, and the antenna 110 are external to the NFC integrated circuit 102.
The EMI low-pass filter 104 comprises a first inductor 104a, a second inductor 104b, a first capacitor 104c, and a second capacitor 104d. The matching network 106 comprises a first capacitor 106a, a second capacitor 106b, a third capacitor 106c, a fourth capacitor 106d, a fifth capacitor 106e, and a sixth capacitor 106f. The phase shifting network 108 comprises a resistor R130 and a capacitor C130. The connectivity of the above circuit elements is shown in
More specifically, the EMI low-pass filter 104 is arranged to filter out the EMI signal of the transmitting NFC signal generated by the PCD transmitter 1030. The matching network 106 is arranged to perform impedance matching between the antenna 110 and the EMI low-pass filter 104 and the impedance matching between the antenna 110 and the switching circuit 1032. The phase shifting network 108 provides a path to receive the NFC signal from the antenna 110 to the PCD receiver 1024 and the PICC receiver 1026 or to receive the transmitting NFC signal from the EMI low-pass filter 104 to the PCD receiver 1024.
In the NFC integrated circuit 102, the baseband processor 1022 is coupled to the PCD receiver 1024, the PICC receiver 1026, the adjusting device 1028, the PCD transmitter 1030, and the switching circuit 1032. The switching circuit 1032 comprises a first switch 1032a and a second switch 1032b. The adjusting device 1028 is arranged for presently adjusting a peak voltage level of a modulation signal Sm on the signal receiving port RX to fall within a predetermined voltage range when the modulation signal Sm appears on the signal receiving port RX. In other words, the adjusting device 1028 adjusts the modulation signal Sm in real time. The adjusting device 1028 comprises a programmable impedance component, such as a programmable resistor 1028a, and an envelope detector 1028b. The programmable resistor 1028a has a first terminal coupled to the signal receiving port RX and a second terminal coupled to a reference voltage, e.g. the ground voltage Vgnd, for providing impedance between the signal receiving port RX and the ground voltage Vgnd according to an adjusting signal Sad. The envelope detector 1028b is coupled to the signal receiving port RX and the baseband processor 1022 for detecting an envelope of the modulation signal Sm to generate a detecting signal Sd. The baseband processor 1022 receives the detecting signal Sd and accordingly generates the adjusting signal Sad to adjust the impedance of the programmable resistor 1028a such that the peak voltage level of the modulation signal Sm on the signal receiving port RX falls within the predetermined voltage range.
It should be noted that the adjusting device 1028 is not limited to adjust the peak voltage level of the modulation signal Sm on the signal receiving port RX to fall within the predetermined voltage range, the adjusting device 1028 may be arranged to adjust the peak voltage level of the modulation signal Sm on the signal receiving port RX to be a predetermined voltage level or to adjust the peak voltage level of the modulation signal Sm on the signal receiving port RX to be a predetermined voltage level in the predetermined voltage range.
According to the embodiment, the NFC apparatus 100 (or the NFC integrated circuit 102) can be configured to operate under a PCD mode or a PICC mode. During the PCD mode, the NFC apparatus 100 functions as an initiator, i.e. the reader. During the PICC mode, the NFC apparatus 100 functions as a card.
When the NFC apparatus 100 is configured as the initiator during the PCD mode, the differential PCD transmitter 1030 emits an ASK modulation signal to the antenna 110 through the EMI low-pass filter 104, which is an optional device, and the matching network 106. The first switch 1032a and the second switch 1032b are closed to connect the capacitor 106c and 106e to the ground voltage Vgnd respectively. Before the PCD receiver 1024 receives a load modulation (LM) signal from the target NFC apparatus (not shown), which is configured as a card (i.e. PICC mode), the NFC apparatus 100 is re-configured. When the NFC apparatus 100 is re-configured, the PCD transmitter 1030 emits a transmitting modulation signal St to the target NFC apparatus. The transmitting modulation signal St is a continuous wave (CW) signal having an oscillating frequency substantially equal to 13.56 MHz as shown in
On the other hand, when the NFC apparatus 100 is configured as the card during the PICC mode, the NFC apparatus 100 receives a receiving modulation signal Sr from the other NFC apparatus which is configured as an initiator. The receiving modulation signal Sr is an ASK modulation signal. The receiving modulation signal Sr is received through the antenna 110, the matching network 106, and the phase shifting network 108 before it is demodulated and decoded by the PICC receiver 1026 as shown
Accordingly, no matter the NFC apparatus 100 is configured to operate under the PCD mode or the PICC mode, the voltage level of the modulation signal Sm on the signal receiving port RX should be fall within an appropriate range such that the PCD receiver 1024 or the PICC receiver 1026 can receive the modulation signal Sm (e.g. the load modulation signal or the receiving modulation signal Sr) correctly.
According to the embodiment, the fixed resistor R130 in the phase shifting network 108 forms a voltage divider with the input impedance ZRX at the signal receiving port RX of the NFC integrated circuit 102. After the values of the resistor R130 and the capacitor C130 are determined, the voltage level of the modulation signal Sm on the signal receiving port RX may only be adjusted by the programmable resistor 1028a in the adjusting device 1028 such that the voltage level of the modulation signal Sm on the signal receiving port RX is adjusted into the usable input dynamic range of the PCD receiver 1024 or the PICC receiver 1026. Please refer to
In the left side of
In addition, the resistance of the programmable resistor 1028a is set to be the maximum value as default, and is gradually reduced by the adjusting device 1028 in real time. This ensures that the envelope of the modulation signal Sm on the common terminal VB always has the maximized carrier-to-noise (CNR) ratio after the adjustment of the adjusting device 1028. Nevertheless, other methods of adjusting the resistor R130 are also possible. Moreover, the resistor R130 is placed externally in this embodiment, and this will provide the flexibility of one-time adjustment with respect to different antenna designs. Obviously, the resistor R130 can also be integrated into the NFC integrated circuit 102.
According to the present method, when the signal level of the receiving signal (i.e. the modulation signal Sm) is too high and beyond the receiver dynamic range, the adjusting device 1028 reduces the resistance of the programmable resistor 1028a to make the signal level of the receiving signal to fall within the dynamic range. When the signal level of the receiving signal is too small and fails to be detected by the PCD receiver 1024 (or the PICC receiver 1026), the adjusting device 1028 increases the resistance of the programmable resistor 1028a to increase the signal level of the receiving signal.
It is noted that the adjusting device is not limited to adjust the peak voltage level of the modulation signal Sm to equal a predetermined voltage level, the adjusting device 1028 may also be designed to adjust the peak voltage level of the modulation signal Sm to fall within a predetermined voltage range as long as the envelope of the modulation signal Sm falls within the dynamic range of NFC integrated circuit 102, which also belongs the scope of the present invention.
According to the embodiment, the adjustment of the adjusting device 1028 will stop when the peak voltage level of the envelope of the modulation signal Sm at the common terminal VB falls within the dynamic voltage range of the NFC integrated circuit 102. If the peak voltage level of the envelope of the modulation signal Sm is still below the minimum threshold voltage VTHmin while the resistance of the programmable resistor 1028a is already in the maximum resistance, then the adjusting device 1028 will terminate the adjustment. Similarly, if the peak voltage level of the envelope of the modulation signal Sm still exceeds the maximum threshold voltage VTHmin while the resistance of the programmable resistor 1028a is already in the minimum resistance, then the adjusting device 1028 will also terminate the adjustment.
By using the present adjusting device 1028, the value of the resistor R130 needs not to be very accurately determined during the design phase because the programmable resistor 1028a will automatically compensate the measurement error or the component variation of the resistor R130 during the PCD mode or the PICC mode. In fact, if the dynamic range of the programmable resistor 1028a is sufficiently large, the adjustment of the resistor R130 during the design phase can be eliminated, thus allowing the resistor R130 to be integrated into the NFC integrated circuit 102.
Please refer to
Please refer to
It is noted that, in another embodiment of the present invention, when the NFC apparatus 100 is configured to be the PCD mode, the adjustment scheme is activated only when NFC apparatus 100 is transmitting a continuous wave signal. When the NFC apparatus 100 is configured to be the PICC mode, the adjustment scheme is activated to detect the magnetic field (i.e. the receiving modulation signal Sr) from the other PCD.
In another embodiment of the present invention, the adjustment scheme is activated periodically when the PCD transmitter 1030 is transmitting the modulation signal St. In this embodiment, the adjustment scheme is always activated during the PICC mode.
Please refer to
Please refer to
Moreover, the proposed adjustment scheme can be implemented for all types of PCD and PICC receivers with different demodulator architectures. The separate PCD and PICC receivers 1024, 1026 can also be merged into a single receiver without affecting the operation of the proposed adjustment scheme as shown in
In another embodiment, the proposed adjustment scheme can also be implemented in a NFC integrated circuit 102 having the PCD receiver 1024 and the PCD transmitter 1030, i.e. without the PICC receiver 1026.
Please refer to
More specifically, when the receiver 10026 operates under the PICC mode, the limiter 10026k is arranged to use the modulation signal at the terminal VB to generate the oscillation signal with 13.56 MHz, but not a limitation, to the phase shifter 10026n. More specifically, in the PICC mode, the oscillation signal is obtained from the carrier of the incoming ASK signal at the terminal VB. This can be done by simply passing the ASK signal through an amplitude limiter (i.e. the limiter 10026k). In the PICC mode, the control signal of the multiplexer 10026m is toggled so that the multiplexer 10026m obtains its input from the output of the limiter 10026k.
When the receiver 10026 operates under the PCD mode, the phase-locked loop 10026l is arranged to use the external reference clock of a local source to generate the oscillation signal with 13.56 MHz, but not a limitation, to the phase shifter 10026n. The oscillation signals generated by the phase shifter 10026n are provided to the ADCs 10026e and 10026j.
In summary, the operation of the proposed adjustment scheme in
Step 1202: Use the PCD receiver 1024 to couple to the signal receiving port RX;
Step 1204: Use the PICC receiver 1026 to couple to the signal receiving port RX;
Step 1206: Use the programmable resistor 1028a to provide an impedance between the signal receiving port RX and the ground voltage Vgnd according to an adjusting signal Sad;
Step 1208: Detect the envelope of the modulation signal Sm to generate the detecting signal Sd; and
Step 1210: Receive the detecting signal Sd and accordingly generate the adjusting signal Sad to adjust the impedance of the programmable resistor 1028a such that the peak voltage level of the modulation signal Sm on the signal receiving port RX falls within the predetermined voltage range.
Briefly, the present invention is to instantly detect the peak voltage level of the modulation signal Sm on the signal receiving port RX of the NFC integrated circuit 102, and accordingly adjust the peak voltage level of the modulation signal Sm to fall within the dynamic range of the NFC integrated circuit 102 by adjusting the programmable resistor 1028a. The adjustment scheme can be activated when transmitting a continuous wave signal, and/or in the PCD mode and/or the PICC mode. By using the proposed adjustment scheme, the value of the resistor R130 needs not to be very accurate during the design phase because the programmable resistor 1028a can be used to adjust the peak voltage level of the modulation signal Sm to fall within the dynamic range of the NFC integrated circuit 102, and the resistor R130 can also be integrated into the NFC integrated circuit 102.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims
1. A short-distance contactless communication apparatus, comprising:
- a receiver, configured to operate under at least a first receiving mode and a second receiving mode, wherein the receiver receives a modulation signal with a first modulation scheme when the receiver is configured to operate under the first receiving mode, and the receiver receives a modulation signal with a second modulation scheme when the receiver is configured to operate under the second receiving mode;
- wherein the receiver utilizes an oscillation signal to receive the modulation signal, and the oscillation signal utilized by the receiver is derived from the modulation signal or derived from a reference clock based on the receiving mode of the receiver.
2. The short-distance contactless communication apparatus of claim 1, wherein the receiver comprises:
- a mixer, arranged for receiving the modulation signal and the oscillation signal; and
- a high-pass filter, arranged to couple to an output of the mixer.
3. The short-distance contactless communication apparatus of claim 1, wherein the receiver comprises:
- a limiter, arranged for receiving the modulation signal;
- a phase-locked loop, arranged for receiving the reference clock; and
- a multiplexer, having two inputs coupled to an output of the limiter and an output of the phase-locked loop respectively.
4. The short-distance contactless communication apparatus of claim 1, further comprising:
- an adjusting device, coupled to the receiver, for adjusting a peak voltage level of the received modulation signal to fall within a predetermined voltage range.
5. A short-distance contactless communication apparatus, comprising:
- a first receiver, coupled to a signal receiving port of the short-distance contactless communication apparatus, capable of operating under a proximity coupling device (PCD) mode and/or a proximity inductively coupled card (PICC) mode; and
- an adjusting device, coupled to the signal receiving port, for adjusting a peak voltage level of a modulation signal on the signal receiving port to fall within a predetermined voltage range.
6. The short-distance contactless communication apparatus of claim 5, wherein the adjusting device presently adjusts the peak voltage level of the modulation signal on the signal receiving port when the short-distance contactless communication apparatus receives the modulation signal via the signal receiving port.
7. The short-distance contactless communication apparatus of claim 5, wherein the adjusting device adjusts the peak voltage level of the modulation signal on the signal receiving port to substantially equal a predetermined voltage level in the predetermined voltage range.
8. The short-distance contactless communication apparatus of claim 5, wherein the adjusting device adjusts the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range during the PCD mode of the short-distance contactless communication apparatus, and the modulation signal is an in-band blocker signal or a load modulation signal.
9. The short-distance contactless communication apparatus of claim 5, which is an integrated NFC (Near field communication) device.
10. The short-distance contactless communication apparatus of claim 5, wherein the modulation signal is anASK (Amplitude-shift keying) signal or a continuous wave (CW) signal having an oscillating frequency substantially equal to 13.56 MHz.
11. The short-distance contactless communication apparatus of claim 5, further comprising:
- a second receiver, coupled to the signal receiving port, capable of operating under a PCD mode or a PICC mode.
12. The short-distance contactless communication apparatus of claim 5, wherein the adjusting device adjusts the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range during the PICC mode of the short-distance contactless communication apparatus, and the modulation signal is a receiving ASK (Amplitude-shift keying) signal of the short-distance contactless communication apparatus.
13. The short-distance contactless communication apparatus of claim 5, furthering comprising: wherein the adjusting device comprises: wherein the baseband processor receives the detecting signal and accordingly generates the adjusting signal to adjust the impedance of the programmable impedance component such that the peak voltage level of the modulation signal on the signal receiving port falls within the predetermined voltage range.
- a baseband processor, coupled to the receiver and the adjusting device; and
- a programmable impedance component, having a first terminal coupled to the signal receiving port and a second terminal coupled to a reference voltage, for providing an impedance between the signal receiving port and the reference voltage according to an adjusting signal; and
- an envelope detector, coupled to the signal receiving port and the baseband processor, for detecting an envelope of the modulation signal to generate a detecting signal;
14. The short-distance contactless communication apparatus of claim 13, wherein the baseband processor adjusts the impedance of the programmable impedance component such that the peak voltage level of the modulation signal on the signal receiving port substantially equals a predetermined voltage level in the predetermined voltage range.
15. A short-distance contactless communication method, comprising:
- using a first receiver capable of operating under a proximity coupling device (PCD) mode and/or a proximity inductively coupled card (PICC) mode to couple to a signal receiving port; and
- adjusting a peak voltage level of a modulation signal on the signal receiving port to fall within a predetermined voltage range.
16. The short-distance contactless communication method of claim 15, wherein the step of adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range comprises:
- presently adjusting the peak voltage level of the modulation signal on the signal receiving port when the modulation signal appears on the signal receiving port.
17. The short-distance contactless communication method of claim 15, wherein the step of adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range comprises:
- adjusting the peak voltage level of the modulation signal on the signal receiving port to substantially equal a predetermined voltage level in the predetermined voltage range.
18. The short-distance contactless communication method of claim 15, wherein the step of adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range comprises:
- adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range during the PCD mode, and the modulation signal is an in-band blocker signal or a load modulation signal.
19. The short-distance contactless communication method of claim 15, wherein the modulation signal is an ASK (Amplitude-shift keying) signal or a continuous wave (CW) signal having an oscillating frequency substantially equal to 13.56 MHz.
20. The short-distance contactless communication method of claim 15, wherein the step of adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range comprises:
- adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range during the PICC mode, and the modulation signal is a receiving ASK (Amplitude-shift keying) signal.
21. The short-distance contactless communication method of claim 15, wherein the step of adjusting the peak voltage level of the modulation signal on the signal receiving port to fall within the predetermined voltage range comprises:
- using a programmable impedance component having a first terminal coupled to the signal receiving port and a second terminal coupled to a reference voltage for providing an impedance between the signal receiving port and the reference voltage according to an adjusting signal;
- detecting an envelope of the modulation signal to generate a detecting signal; and
- receiving the detecting signal and accordingly generating the adjusting signal to adjust the impedance of the programmable impedance component such that the peak voltage level of the modulation signal on the signal receiving port falls within the predetermined voltage range.
22. The short-distance contactless communication method of claim 21, wherein the step of receiving the detecting signal and accordingly generating the adjusting signal to adjust the impedance of the programmable resistor comprises:
- adjusting the impedance of the programmable impedance component such that the peak voltage level of the modulation signal on the signal receiving port substantially equals a predetermined voltage level in the predetermined voltage range.
23. A NFC device comprising an NFC integrated circuit (IC) capable of supporting PCD and PICC reception, comprising:
- PCD and PICC receivers have a common input port;
- a fixed resistor coupled to the common input port;
- an envelope detector coupled to the common input port;
- a programmable resistor circuit having a first node coupled to the common input port and a second node coupled to ground;
- wherein the resistance of the programmable resistor circuit is adjusted according to the peak voltage level at the input of the envelope detector, and the adjustment of the programmable resistor circuit continues until the peak voltage at the input of the envelope detector is within a predetermined voltage range.
24. The NFC device of claim 23, wherein the fixed resistor is placed within the NFC integrated circuit.
25. The NFC device of claim 23, wherein during the PCD mode, the adjustment of the programmable resistor circuit is done at least once.
26. The NFC device of claim 23, wherein during the PICC mode, the adjustment of the programmable resistor circuit is done at least once.
27. The NFC device of claim 23, wherein the PCD and PICC receivers are integrated as a single receiver.
Type: Application
Filed: Sep 4, 2014
Publication Date: Mar 5, 2015
Inventors: Chee-Lee Heng (Singapore), WEIMIN SHU (Singapore)
Application Number: 14/476,749
International Classification: H04B 5/00 (20060101); H04L 27/02 (20060101); H04W 4/00 (20060101);