U.S. patent application number 13/360414 was filed with the patent office on 2013-08-01 for mobile wireless communications device including sensing transistor and hysteretic comparator and related methods.
This patent application is currently assigned to Research In Motion Limited. The applicant listed for this patent is Khurram MUHAMMAD, Seong-Ryong Ryu. Invention is credited to Khurram MUHAMMAD, Seong-Ryong Ryu.
Application Number | 20130196719 13/360414 |
Document ID | / |
Family ID | 46466100 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130196719 |
Kind Code |
A1 |
MUHAMMAD; Khurram ; et
al. |
August 1, 2013 |
MOBILE WIRELESS COMMUNICATIONS DEVICE INCLUDING SENSING TRANSISTOR
AND HYSTERETIC COMPARATOR AND RELATED METHODS
Abstract
A mobile wireless communications device may include a portable
housing, and a supply modulator carried by the portable housing.
The supply modulator may include an output node, a linear amplifier
coupled to the output node, and a switching amplifier also coupled
to the output node. The switching amplifier may include at least
one sensing transistor configured to sense current output from the
linear amplifier and generate a drive voltage, and a hysteretic
comparator coupled to the at least one sensing transistor and
configured to be driven by the drive voltage. The mobile wireless
communications device may also include a radio frequency (RF) power
amplifier coupled to the output node of the supply modulator, and a
wireless transceiver carried by the portable housing and coupled to
the RF power amplifier.
Inventors: |
MUHAMMAD; Khurram; (Garland,
TX) ; Ryu; Seong-Ryong; (Richardson, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MUHAMMAD; Khurram
Ryu; Seong-Ryong |
Garland
Richardson |
TX
TX |
US
US |
|
|
Assignee: |
Research In Motion Limited
Waterloo
CA
|
Family ID: |
46466100 |
Appl. No.: |
13/360414 |
Filed: |
January 27, 2012 |
Current U.S.
Class: |
455/571 |
Current CPC
Class: |
H03F 2200/432 20130101;
H03F 2200/462 20130101; H03F 3/245 20130101; H03F 1/0227 20130101;
H03F 2200/451 20130101; H04B 1/04 20130101; H03F 2200/102 20130101;
H03F 3/2173 20130101; H03F 3/19 20130101 |
Class at
Publication: |
455/571 |
International
Class: |
H04B 1/40 20060101
H04B001/40 |
Claims
1. A mobile wireless communications device comprising: a portable
housing; a supply modulator carried by said portable housing and
comprising an output node, a linear amplifier coupled to said
output node, and a switching amplifier also coupled to said output
node and comprising at least one sensing transistor configured to
sense current output from said linear amplifier and generate a
drive voltage, and a hysteretic comparator coupled to said at least
one sensing transistor and configured to be driven by the drive
voltage; a radio frequency (RF) power amplifier coupled to said
output node of said supply modulator; and a wireless transceiver
carried by said portable housing and coupled to said RF power
amplifier.
2. The mobile wireless communications device of claim 1, wherein
said switching amplifier further comprises at least one current
conveyor circuit coupled to said at least one sensing transistor
and configured to control a bias of said at least one sensing
transistor.
3. The mobile wireless communications device of claim 1, wherein
said linear amplifier comprises an operational transconductance
amplifier and at least one transistor coupled thereto.
4. The mobile wireless communications device of claim 1, wherein
said switching amplifier further comprises a buffer coupled between
said hysteretic comparator and said output node.
5. The mobile wireless communications device of claim 4, wherein
said buffer comprises a pair of transistors having respective
control terminals coupled to each other.
6. The mobile wireless communications device of claim 1, wherein
said switching amplifier further comprises at least one inductor
coupled between said output node and said buffer.
7. The mobile wireless communications device of claim 1, wherein
said wireless transceiver comprises a cellular transceiver.
8. A supply modulator to be carried by a portable housing of a
mobile wireless communications device comprising a radio frequency
(RF) power amplifier and a wireless transceiver carried by the
portable housing and coupled to the RF power amplifier, the supply
modulator comprising: an output node coupled to be coupled to the
RF power amplifier; a linear amplifier coupled to said output node;
and a switching amplifier also coupled to said output node and
comprising at least one sensing transistor configured to sense
current output from said linear amplifier and generate a drive
voltage, and a hysteretic comparator coupled to said at least one
sensing transistor and configured to be driven by the drive
voltage.
9. The supply modulator of claim 8, wherein said switching
amplifier further comprises at least one current conveyor circuit
coupled to said at least one sensing transistor and configured to
control a bias of said at least one sensing transistor.
10. The supply modulator of claim 8, wherein said linear amplifier
comprises an operational transconductance amplifier and at least
one transistor coupled thereto.
11. The supply modulator of claim 8, wherein said switching
amplifier further comprises a buffer coupled between said
hysteretic comparator and said output node.
12. The supply modulator of claim 11, wherein said buffer comprises
a pair of transistors having respective control terminals coupled
to each other.
13. The supply modulator of claim 8, wherein said switching
amplifier further comprises at least one inductor coupled between
said output node and said buffer.
14. A method of operating a supply modulator for a power amplifier
of a mobile wireless communications device, the supply modulator
comprising an output node, a linear amplifier coupled to the output
node, and a switching amplifier coupled to the linear amplifier,
method comprising: using the switching amplifier to sense current
output from the linear amplifier via at least one sensing
transistor, generate a drive voltage via the at least one sensing
transistor, and drive a hysteretic comparator coupled to the at
least one sensing transistor with the drive voltage.
15. The method of claim 14, wherein the switching amplifier further
comprises at least one current conveyor circuit coupled to the at
least one sensing transistor; and wherein the switching amplifier
is used to control a bias of the at least one sensing
transistor.
16. The method of claim 14, wherein the switching amplifier further
comprises a buffer coupled between the hysteretic comparator and
the output node.
17. The method of claim 16, wherein the buffer comprises a pair of
transistors having respective control terminals coupled to each
other.
18. The method of claim 14, wherein the switching amplifier further
comprises at least one inductor coupled between the output node and
the buffer.
Description
TECHNICAL FIELD
[0001] The present disclosure generally relates to the field of
wireless communications systems, and, more particularly, to mobile
wireless communications devices and related methods.
BACKGROUND
[0002] Mobile wireless communications systems continue to grow in
popularity and have become an integral part of both personal and
business communications. For example, cellular telephones allow
users to place and receive voice calls almost anywhere they travel,
while tablet personal computers allow mobile data communications
almost anywhere. Moreover, as mobile communications technology, for
example, cellular communications technology, has increased, so too
has the functionality of cellular devices and the different types
of devices available to users. For example, many cellular devices
now incorporate personal digital assistant (PDA) features such as
calendars, address books, task lists, etc. Moreover, such
multi-function devices, including, for example, tablet personal
computers, may also allow users to wirelessly send and receive
electronic mail (email) messages and access the Internet via a
cellular network and/or a wireless local area network (WLAN), for
example.
[0003] Even so, as the functionality of cellular communications
devices continues to increase, so too does the demand for smaller
devices which are easier and more convenient for users to carry.
One challenge this poses for cellular device manufacturers is
designing communications circuitry, including, for example, an RF
transmitter, for increased operational and performance stability
within the relatively limited amount of space available for the
communications circuitry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a perspective view of a mobile wireless
communications device including a supply modulator in accordance
with one exemplary aspect.
[0005] FIG. 2 is a schematic block diagram of a portion of the
mobile wireless communications device of FIG. 1 including the
supply modulator.
[0006] FIG. 3 is a schematic diagram of the current sensor and
hysteretic comparator of FIG. 2.
[0007] FIG. 4 is a schematic diagram of a system level connection
of the linear amplifier and current sensor of FIG. 2.
[0008] FIG. 5 is a schematic block diagram illustrating additional
components that may be included in the electronic device of FIG.
1.
DETAILED DESCRIPTION
[0009] The present description is made with reference to the
accompanying drawings, in which various embodiments are shown.
However, many different embodiments may be used, and thus the
description should not be construed as limited to the embodiments
set forth herein. Rather, these embodiments are provided so that
this disclosure will be thorough and complete. Like numbers refer
to like elements throughout.
[0010] In accordance with an exemplary aspect, a mobile wireless
communications device may include a portable housing, and a supply
modulator carried by the portable housing. The supply modulator may
include an output node, a linear amplifier coupled to the output
node, and a switching amplifier also coupled to the output node,
for example. The switching amplifier may include at least one
sensing transistor configured to sense current output from the
linear amplifier and generate a drive voltage, and a hysteretic
comparator coupled to the at least one sensing transistor and
configured to be driven by the drive voltage. The mobile wireless
communications device may also include a radio frequency (RF) power
amplifier coupled to the output node of the supply modulator, and a
wireless transceiver carried by the portable housing and coupled to
the RF power amplifier, for example.
[0011] The switching amplifier may further include at least one
current conveyor circuit coupled to the at least one sensing
transistor. The at least one current conveyor circuit may be
configured to control a bias of the at least one sensing
transistor. The linear amplifier may include an operational
transconductance amplifier and at least one transistor coupled
thereto, for example.
[0012] The switching amplifier may further include a buffer coupled
between the hysteretic comparator and the output node. The buffer
may include a pair of transistors having respective control
terminals coupled to each other.
[0013] The switching amplifier may further include at least one
inductor coupled between the output node and the buffer. The
wireless transceiver may include a cellular transceiver, for
example.
[0014] A method aspect is directed to a method of operating a
supply modulator for a power amplifier of a mobile wireless
communications device. The supply modulator may include an output
node, a linear amplifier coupled to the output node, and a
switching amplifier coupled to the linear amplifier. The method may
include using the switching amplifier to sense current output from
the linear amplifier via at least one sensing transistor and
generate a drive voltage via the at least one sensing transistor,
and drive a hysteretic comparator coupled to the at least one
sensing transistor with the drive voltage.
[0015] Referring initially to FIGS. 1-2, a mobile wireless
communications device 20, which may be, for example, a cellular
communications device, illustratively includes a portable housing
21. A printed circuit board (PCB) may be carried by the portable
housing. In some embodiments, the PCB may be replaced by or used in
conjunction with a metal chassis or other substrate. The PCB may
also include a conductive layer defining a ground plane.
[0016] The exemplary mobile wireless communications device 20
further illustratively includes a display 23 and a plurality of
control keys including an "off hook" (i.e., initiate phone call)
key 24, an "on hook" (i.e., discontinue phone call) key 25, a menu
key 26, and a return or escape key 27. Operation of the various
device components and input keys, etc., will be described further
below with reference to FIG. 5.
[0017] The mobile wireless communications device 20 further
illustratively includes a radio frequency (RF) power amplifier (PA)
32. An antenna 66 is coupled between an output of the RF power
amplifier 32. A wireless transceiver 33 is carried by the portable
housing and coupled to the RF power amplifier 32. The wireless
transceiver 33 may be a cellular transceiver, for example. Of
course, the wireless transceiver 33 may be another type of
transceiver.
[0018] The mobile wireless communications device 20 also includes a
supply modulator 40 carried by the portable housing 21. The supply
modulator 40 may be configured to track an envelope of the RF power
amplifier 32. The supply modulator may be considered a
hybrid-supply modulator, as will be appreciated by those skilled in
the art. The supply modulator 40 includes an output node 41 coupled
to the RF power amplifier 32 and a linear amplifier (LA) 50 coupled
to the output node. The linear amplifier 50 also includes an output
stage, which will be described in further detail below.
[0019] The supply modulator 40 also includes a switching amplifier
60 also coupled to the output node 41. The supply modulator 40
advantageously provides a variable supply voltage to the RF power
amplifier 32 to increase overall power efficiency.
[0020] The switching amplifier 60 includes a current sensor 65 that
includes sensing transistors M1, M6 configured to sense current
output from the linear amplifier 50 and generate a drive voltage.
The switching amplifier 60 also includes a hysteretic comparator 70
coupled to the sensing transistors M1, M6. The hysteretic
comparator 70 is configured to be driven by the drive voltage. An
inductor 62 is coupled between a buffer 52 and the output node 41.
In other words, the buffer 52 is coupled between the hysteretic
comparator 70 and the inductor 62. The inductor 62 generates the
current for the RF power amplifier 32. As will be discussed in
further detail below, ideally the average output current of the
linear amplifier 50 is supposed to be zero for maximum power
efficiency. The buffer 52 generates pulses with variable duty ratio
depending on the output current of the linear amplifier 50. For
instance, if the output current of the linear amplifier 50 is less
than zero, than the duty ratio becomes larger so that the inductor
62 stores and provides more current to decrease the output current
of the linear amplifier.
[0021] Referring now additionally to FIGS. 3 and 4, the various
components, and more particularly, the supply modulator 40 are
described in further detail. In the supply modulator 40, the duty
ratio of the switching amplifier 60 is dynamically adjusted to set
the output current of the linear amplifier 50 to zero and
determined by the output current level of linear amplifier. For
example, if output current of the linear amplifier 50 is greater
than zero, then the duty ratio increases to reduce the output
current of linear amplifier back to zero. In contrast, the duty
ratio decreases to rise up the output current of the linear
amplifier 50 when it is below zero.
[0022] As will be appreciated by those skilled in the art, an
output current of zero from the linear amplifier 50 is highly
desired. This is because the closer to zero the output current from
the linear amplifier 50 is, the more efficiently the RF power
amplifier 32 operates. In other words, if the output current of the
linear amplifier 50 is zero, the RF power amplifier 32 operates at
maximum efficiency, as will be appreciated by those skilled in the
art.
[0023] To accomplish this functionality, the current sensor 65
senses the output current of linear amplifier 50 and then
transforms the sensed current to a control voltage to drive the
hysteretic comparator 70, which in turn generates a rail-to-rail
control signal to the buffer 52 coupled between the hysteretic
comparator and the output node 41. The buffer 52 includes a pair of
transistors 53, 54, and more particularly, power amplifiers, having
respective control terminals coupled to each other. An inverter
chain 55 and more particularly, an output of the inverter chain is
also coupled to the control terminals of the pair of power
transistors 53, 54. The input of the inverter chain 55 is coupled
to the output of the hysteretic comparator 70. Thus, an increased
accuracy, quicker, and more power efficient current sensor may be
desired for relatively highly efficient operation.
[0024] One prior art method of sensing the output current of the
linear amplifier 50 includes inserting a resistor in series with
the output of the linear amplifier to monitor the output current of
the linear amplifier by measuring the voltage across the resistor.
Though this method may be implemented relatively easily, the
resistor may cause additional power consumption, which decreases
power efficiency. This may be particularly important in a mobile
wireless communications device, for example.
[0025] Advantageously, as in the present embodiments, the output
current of the linear amplifier 50 may be sensed by measuring the
current difference between the output stage transistors MN, MP,
which are in the form of NMOS and PMOS transistors, respectively.
In other words, the current sensing is done without a sensing
resistor. It should be noted that the output current of the linear
amplifier 50 may be about equal to the current difference between
the drain currents of the output stage transistors MN, MP. Scaled
sensing NMOS and PMOS transistors M1, M6 are added, and their gate
and source terminals are connected to the output stage NMOS and
PMOS transistors MN, MP respectively. It is also worthy to note
that typically, the sensing transistors M1, M6 have much shorter
gate widths and, thus flow much lower current than the output stage
transistors MN, MP. Due to the same voltage biases at their gate
and source terminals, if the sensing transistors M1, M6 have the
same drain voltage bias as the drain bias of the output transistors
MN, MP, than a relatively accurately scaled copy of the output
stage current may flow through the sensing transistors.
Conventionally, a feedback loop formed by operational amplifiers
may be employed for the drain bias control.
[0026] The output stage of the linear amplifier 50 also includes an
operational transconductance amplifier (OTA) 56 configured to
receive input voltage (FIG. 4). The output of the OTA 56 is coupled
to a class AB bias circuit 57, which is coupled to the control
terminals of the output stage transistors MN, MP. The functionality
of the OTA 56 and the class AB bias circuit 57 will be appreciated
by those skilled in the art.
[0027] In the present embodiments, instead of using operational
amplifiers, the current sensor 65 also includes two
current-conveyors 68, 69 to control the drain biases of the sensing
transistors, M1 and M6. The current-conveyors 68, 69 are
implemented by using eight MOS transistors M2-M5, M7-M10, and
together have several advantages over operational amplifiers, as
will be appreciated by those skilled in the art. First, the current
conveyors 68, 69 may use a less number of the transistors meaning
that its implementation may be simpler. Secondly, the current
conveyors 68, 69 may have a wider bandwidth than operational
amplifiers. Thus, the cost, frequency response, and power
efficiency may be improved. Other configurations may be
implemented, for example, by using a different number and/or
different type of transistors in a different arrangement.
[0028] Assuming the transistors are in the saturation region, the
voltages at INC, and nodes between M6 and M8, and M3 and M1 may be
identical or close to identical due to two feedback loops formed by
four current mirrors, which are formed by M2 and M3, M4 and M5, M7
and M8, and M9 and M10. Moreover, since gate and source terminals
of MN and M1, and MP and M6 are coupled to each other, then M1 and
M6 may flow the scaled copy of the drain current of MN and MP,
respectively, due to their same gate-to-source and drain-to-source
voltage bias condition. The copied currents by M1 and M6 are in
turn mirrored by transistors, M11-M18, and then converted to the
differential voltage signal through transistors, M19-M22, where
M16, M17 and M18 are to bias the current buffer transistor M13, and
the current buffer may decrease the current error between M5 and
M12 caused by bias mismatching. The differential voltage signal is
applied to the inputs of the hysteretic comparator 70, which is
implemented by ten transistors, M23-M32, and has relatively the
same topology as a conventional hysteretic comparator. Lastly, the
hysteretic comparator 70 generates the rail-to-rail control signal
to drive the buffer 52.
[0029] One potential drawback of the embodiments described herein
is that when the output voltage level of the linear amplifier 50 is
relatively close to the supply voltage level (VDD or VSS), one of
the current conveyors 68, 69 may underperform since M4 or M9 may
fall into the linear region due to its limited voltage headroom,
hence decreasing, by a relatively small margin, the sensing
accuracy. However, the sensitivity of the current sensor 65 may be
most critical at the average output signal level of the linear
amplifier 50, which is equal to the average envelope signal level
and close to the middle of the supply level, (VDD+VSS)/2. Thus, the
power efficiency may not be degraded due to the sensitivity
reduction.
[0030] A method aspect is directed to a method of operating a
supply modulator 40 for a power amplifier 32 of a mobile wireless
communications device 20. The supply modulator 40 includes an
output node 41, a linear amplifier 50 coupled to the output node,
and a switching amplifier 60 coupled to the linear amplifier. The
method includes using the switching amplifier 60 to sense current
output from the linear amplifier 50 via at sensing transistors M1,
M6. The method also includes using the switching amplifier 60 to
generate a drive voltage via the sensing transistors M1, M6, and
drive a hysteretic comparator 70 coupled to the sensing transistors
with the drive voltage.
[0031] Example components of a mobile wireless communications
device 1000 that may be used in accordance with the above-described
embodiments are further described below with reference to FIG. 5.
The device 1000 illustratively includes a housing 1200, a keyboard
or keypad 1400 and an output device 1600. The output device shown
is a display 1600, which may comprise a full graphic LCD. Other
types of output devices may alternatively be utilized. A processing
device 1800 is contained within the housing 1200 and is coupled
between the keypad 1400 and the display 1600. The processing device
1800 controls the operation of the display 1600, as well as the
overall operation of the mobile device 1000, in response to
actuation of keys on the keypad 1400.
[0032] The housing 1200 may be elongated vertically, or may take on
other sizes and shapes (including clamshell housing structures).
The keypad may include a mode selection key, or other hardware or
software for switching between text entry and telephony entry.
[0033] In addition to the processing device 1800, other parts of
the mobile device 1000 are shown schematically in FIG. 5. These
include a communications subsystem 1001; a short-range
communications subsystem 1020; the keypad 1400 and the display
1600, along with other input/output devices 1060, 1080, 1100 and
1120; as well as memory devices 1160, 1180 and various other device
subsystems 1201. The mobile device 1000 may comprise a two-way RF
communications device having data and, optionally, voice
communications capabilities. In addition, the mobile device 1000
may have the capability to communicate with other computer systems
via the Internet.
[0034] Operating system software executed by the processing device
1800 is stored in a persistent store, such as the flash memory
1160, but may be stored in other types of memory devices, such as a
read only memory (ROM) or similar storage element. In addition,
system software, specific device applications, or parts thereof,
may be temporarily loaded into a volatile store, such as the random
access memory (RAM) 1180. Communications signals received by the
mobile device may also be stored in the RAM 1180.
[0035] The processing device 1800, in addition to its operating
system functions, enables execution of software applications
1300A-1300N on the device 1000. A predetermined set of applications
that control basic device operations, such as data and voice
communications 1300A and 1300B, may be installed on the device 1000
during manufacture. In addition, a personal information manager
(PIM) application may be installed during manufacture. The PIM may
be capable of organizing and managing data items, such as e-mail,
calendar events, voice mails, appointments, and task items. The PIM
application may also be capable of sending and receiving data items
via a wireless network 1401. The PIM data items may be seamlessly
integrated, synchronized and updated via the wireless network 1401
with corresponding data items stored or associated with a host
computer system.
[0036] Communication functions, including data and voice
communications, are performed through the communications subsystem
1001, and possibly through the short-range communications
subsystem. The communications subsystem 1001 includes a receiver
1500, a transmitter 1520, and one or more antennas 1540 and 1560.
In addition, the communications subsystem 1001 also includes a
processing module, such as a digital signal processor (DSP) 1580,
and local oscillators (LOs) 1601. The specific design and
implementation of the communications subsystem 1001 is dependent
upon the communications network in which the mobile device 1000 is
intended to operate. For example, a mobile device 1000 may include
a communications subsystem 1001 designed to operate with the
Mobitex.TM., Data TAC.TM. or General Packet Radio Service (GPRS)
mobile data communications networks, and also designed to operate
with any of a variety of voice communications networks, such as
AMPS, TDMA, CDMA, WCDMA, PCS, GSM, EDGE, etc. Other types of data
and voice networks, both separate and integrated, may also be
utilized with the mobile device 1000. The mobile device 1000 may
also be compliant with other communications standards such as 3GSM,
3GPP, UMTS, 4G, etc.
[0037] Network access requirements vary depending upon the type of
communication system. For example, in the Mobitex and DataTAC
networks, mobile devices are registered on the network using a
unique personal identification number or PIN associated with each
device. In GPRS networks, however, network access is associated
with a subscriber or user of a device. A GPRS device therefore
typically involves use of a subscriber identity module, commonly
referred to as a SIM card, in order to operate on a GPRS
network.
[0038] When required network registration or activation procedures
have been completed, the mobile device 1000 may send and receive
communications signals over the communication network 1401. Signals
received from the communications network 1401 by the antenna 1540
are routed to the receiver 1500, which provides for signal
amplification, frequency down conversion, filtering, channel
selection, etc., and may also provide analog to digital conversion.
Analog-to-digital conversion of the received signal allows the DSP
1580 to perform more complex communications functions, such as
demodulation and decoding. In a similar manner, signals to be
transmitted to the network 1401 are processed (e.g. modulated and
encoded) by the DSP 1580 and are then provided to the transmitter
1520 for digital to analog conversion, frequency up conversion,
filtering, amplification and transmission to the communication
network 1401 (or networks) via the antenna 1560.
[0039] In addition to processing communications signals, the DSP
1580 provides for control of the receiver 1500 and the transmitter
1520. For example, gains applied to communications signals in the
receiver 1500 and transmitter 1520 may be adaptively controlled
through automatic gain control algorithms implemented in the DSP
1580.
[0040] In a data communications mode, a received signal, such as a
text message or web page download, is processed by the
communications subsystem 1001 and is input to the processing device
1800. The received signal is then further processed by the
processing device 1800 for an output to the display 1600, or
alternatively to some other auxiliary I/O device 1060. A device may
also be used to compose data items, such as e-mail messages, using
the keypad 1400 and/or some other auxiliary I/O device 1060, such
as a touchpad, a rocker switch, a thumb-wheel, or some other type
of input device. The composed data items may then be transmitted
over the communications network 1401 via the communications
subsystem 1001.
[0041] In a voice communications mode, overall operation of the
device is substantially similar to the data communications mode,
except that received signals are output to a speaker 1100, and
signals for transmission are generated by a microphone 1120.
Alternative voice or audio I/O subsystems, such as a voice message
recording subsystem, may also be implemented on the device 1000. In
addition, the display 1600 may also be utilized in voice
communications mode, for example to display the identity of a
calling party, the duration of a voice call, or other voice call
related information.
[0042] The short-range communications subsystem enables
communication between the mobile device 1000 and other proximate
systems or devices, which need not necessarily be similar devices.
For example, the short-range communications subsystem may include
an infrared device and associated circuits and components, a
Bluetooth.TM. communications module to provide for communication
with similarly-enabled systems and devices, or a near field
communications (NFC) sensor for communicating with a NFC device or
NFC tag via NFC communications.
[0043] Many modifications and other embodiments will come to the
mind of one skilled in the art having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is understood that various modifications
and embodiments are intended to be included within the scope of the
appended claims.
* * * * *