Communication between wireless devices capable of communicating using multiple MAC protocols

A first wireless device and a second wireless device are each capable of communicating using multiple MAC protocols. The first wireless device sets a first receiver to a power savings mode, the first receiver designed to operate according to a first MAC protocol. The first wireless device then receives, from the second wireless device, an indication on a second receiver corresponding to a second MAC protocol that data is available to be transmitted to the first wireless device from the second wireless device. In response to receipt of the indication, the first wireless sets the first receiver to an active mode, and receives the data from the second wireless device using the first receiver operating in accordance with the first MAC protocol. The second receiver consumes less power than the first receiver. Reduction of power consumption in the first wireless device may be achieved.

BACKGROUND

1. Technical Field

Embodiments of the present disclosure relate generally to wireless devices, and more specifically to communication between wireless devices capable of communicating using multiple MAC (medium access control) protocols.

2. Related Art

A wireless device refers to a device communicating with one or more other devices using a wireless medium. MAC protocols are the basis for sharing a wireless medium among multiple devices, particularly when the communication ranges of such devices overlap. Frequency division multiplexing, time division multiplexing, code division multiple access, carrier sense multiple access (CSMA CD/CSMA CA), etc., are the common techniques forming the basis for MAC protocols.

Wireless devices are often provided the capability to communicate using multiple MAC protocols. For example, devices are often provided capabilities to communicate using IEEE 802.11 standards (also referred to as WLAN or WiFi™, Bluetooth™, Bluetooth Low Energy (BLE), GSM, etc., as suited in corresponding environments.

Aspects of the present disclosure are directed to communication between wireless devices provided with such capabilities to communicate using multiple MAC protocols.

DETAILED DESCRIPTION

According to an aspect of the present disclosure, a first wireless device and a second wireless device are each capable of communicating using multiple MAC protocols. The first wireless device sets a first receiver to a power savings mode, with the first receiver being designed to operate according to a first MAC protocol. The first wireless device then receives, from the second wireless device, an indication on a second receiver corresponding to a second MAC protocol that data is available to be transmitted to the first wireless device from the second wireless device. In response to receipt of the indication, the first wireless sets the first receiver to an active mode, and receives the data from the second wireless device using the first receiver operating in accordance with the first MAC protocol.

In an embodiment, the first wireless device and second wireless device are respectively a wireless station and an access point according to IEEE 802.11 (WLAN) standards, the first MAC protocol is the WLAN protocol and the second MAC protocol is the BLE MAC protocol. Due to the higher bandwidth at which receivers of WLAN protocol operate (compared to BLE), data transfer may be accomplished in a shorter duration. As receivers with BLE protocol operate at lower power consumption, the power consumption in the first wireless device during idle transmit/receive durations is reduced.

Several aspects of the invention are described below with reference to examples for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the invention. One skilled in the relevant arts, however, will readily recognize that the invention can be practiced without one or more of the specific details, or with other methods, etc. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the features of the invention.

2. Example Environment

FIG. 1is a block diagram representing an example environment in which several aspects of the present disclosure can be implemented. The example environment is shown containing only representative devices and systems for illustration. However, real world environments may contain more or fewer systems.FIG. 1is shown containing wireless devices110,120and150, and internet190. Only three wireless devices are shown for conciseness. However, the environment ofFIG. 1may contain more than three wireless devices also.

Internet190extends the connectivity of wireless devices110,120and150to various systems (not shown) connected to Internet190, and is shown connected to wireless device110on a wired path191. Wireless devices120and150may access devices/systems in internet190via wireless device110. Internet190may be implemented using protocols such as IP. In general, in IP environments, an IP packet is used as a basic unit of transport, with the source address being set to the IP address assigned to the source system from which the packet originates and the destination address set to the IP address of the destination system to which the packet is to be eventually delivered. The IP packet is encapsulated in the payload of layer-2 packets when being transported across WLANs.

An IP packet is said to be directed to a destination system when the destination IP address of the packet is set to the IP address of the destination system, such that the packet is eventually delivered to the destination system. When the packet contains content such as port numbers, which specifies the destination application, the packet may be said to be directed to such application as well. The destination system may be required to keep the corresponding port numbers available/open, and process the packets with the corresponding destination ports.

Wireless devices110,120and150are capable of communicating with each other on a wireless medium, and using multiple MAC protocols. Thus, wireless device110is shown containing antennas115and116, each antenna for wireless communication using a corresponding one of two MAC protocols. Similarly, wireless device120is shown containing antennas125and126, each for wireless communication using a corresponding one of two MAC protocols (and corresponding receivers), and wireless device150is shown containing antennas155and156, each for wireless communication using a corresponding one of two MAC protocols. Each of wireless devices110,120and150is assumed to contain corresponding RF (radio frequency) and baseband processing circuits for enabling communication (transmission and/or reception) using each of the corresponding protocols.

In the wireless devices ofFIG. 1, a separate antenna is shown as being used for transmitting and receiving wireless signals according to each MAC protocol. However, a same (single) antenna can also be used for transmitting and receiving wireless signals of multiple MAC protocols (of respective receiver and transmitter circuits). The IP protocol noted above operates on top of such MAC protocols.

InFIG. 1, wireless signals130depict communication between wireless devices110and120using one MAC protocol (and using antennas115and125), and wireless signals140depict communication between wireless devices110and120using another MAC protocol (and using antennas116and126). Similar communication using the two protocols can occur between wireless devices110and150as well. Wireless devices may be deployed with the capability to communicate with multiple MAC protocols, for example, to be able to communicate with multitude of devices with corresponding communication capabilities.

The description is continued with the description of a flowchart illustrating the manner in which one such wireless device communicates with another such wireless device, for reduced power consumption, in an embodiment.

3. Reducing Power Consumption in a Wireless Device

FIG. 2is a flow chart illustrating the manner in which a wireless device communicates with another wireless, in an embodiment of the present disclosure. Merely for illustration, the flowchart is described below as being performed in wireless device120, which is assumed to require operation in power savings mode when communicating with wireless device110. However, the features can be implemented in the other wireless devices ofFIG. 1, as well as other systems and environments also without departing from the scope and spirit of various aspects of the present invention, as will be apparent to one skilled in the relevant arts by reading the disclosure provided herein.

In step210, wireless device120transitions to a power savings mode in the operation of a first receiver contained in wireless device120. The first receiver operates according to a first MAC protocol, and may represent either the RF portion alone of the receiver or RF and baseband signal processing portions of the first receiver. One or both of the RF (which normally consumes high power when operational) as well as baseband signal processing portions may be powered down when the first receiver is in power savings mode. When in the power savings mode, the first receiver is incapable of receiving data. Control then passes to step220.

In step220, wireless device120receives, from wireless device110, on a second receiver contained in wireless device120, an indication that data is available to be transmitted to wireless device120from wireless device110. The second receiver operates according to a second MAC protocol. The indication may be received after wireless device120transitions to the power savings mode (in step210). Control then passes to step230.

In step230, wireless device120, in response to receiving the indication (of step220), transitions to an active mode in the operation of the first receiver, and receives data from wireless device110using the first receiver according to the first MAC protocol. Thus, on receiving the indication from wireless device110, the portions of the first receiver which were powered down (in step210) are powered ON, and are used to receive data from wireless device110. Control then passes to step210, and the corresponding steps of the flowchart ofFIG. 2may be repeated.

FIG. 3is another flowchart illustrating the manner in which a wireless device communicates with another wireless device. Merely for illustration, the flowchart ofFIG. 3is described below as being performed in wireless device110, to enable power savings in wireless device120in accordance with the description ofFIG. 2above. However, the features can be implemented in the other wireless devices ofFIG. 1, as well as other systems and environments also without departing from the scope and spirit of various aspects of the present invention, as will be apparent to one skilled in the relevant arts by reading the disclosure provided herein. In addition, some of the steps may be performed in a different sequence than that depicted below, as suited to the specific environment, as will be apparent to one skilled in the relevant arts. Many of such implementations are contemplated to be covered by several aspects of the present disclosure. The flow chart begins in step301, in which control immediately passes to step310.

In step310, wireless device110receives an indication that a first receiver in wireless device120is transitioning to power savings mode. The first receiver operates according to a first MAC protocol. Wireless device110may receive the indication via a receiver contained in wireless device110that also operates according to the first MAC protocol. Control than passes to step320.

In step320, wireless device110identifies a data unit for transmission to wireless device120. The data unit may correspond to one received from an external device/system, such as for example, wireless device150or a device in internet190. Control then passes to step330.

In step330, wireless device110sends an indication to wireless device120using a second MAC protocol to indicate that data is available to be transmitted to wireless device120from wireless device110. Wireless device110may send the indication via a transmitter in wireless device110that operates according to the second MAC protocol, and wireless device120may receive the indication via a receiver in wireless device120that operates according to the second MAC protocol. Wireless device110may send the indication of data availability at a time instance later than when wireless device110receives the indication of step310. Control then passes to step340.

In step340, wireless device110, after sending the indication of step330, transmits the data unit to wireless device120using the first MAC protocol. Wireless device110may transmit the data via a transmitter in wireless device110that operates according to the first MAC protocol. Wireless device120may receive the data unit via the first receiver, and process the data unit suitably, after which wireless device110may again set the first receiver to power savings mode. Control then passes to step310, and the corresponding steps may be repeated.

The first MAC protocol and the second MAC protocol noted in the flowcharts ofFIG. 2andFIG. 3are the same. The steps of the flowcharts ofFIG. 2andFIG. 3may be co-operatively performed by wireless devices110and120. It is also noted that wireless device110may maintain a list of all wireless devices (such as wireless device120) which are ‘presently’ in power savings mode, and inspect the list to check if a corresponding wireless device is present in the list whenever wireless device110has data to be transmitted to that wireless device. Wireless device110may then send an indication using the second MAC protocol to the wireless device indicating that data is available to be transmitted.

In an embodiment of the present disclosure, wireless device110and wireless device120referred to in the flowcharts ofFIG. 2andFIG. 3are respectively an access point (AP, referred to below as AP110) and a wireless station (STA, referred to below as STA120) according to IEEE 802.11 standards, the first MAC protocol is the IEEE 802.11 (WLAN) MAC protocol, and the second MAC protocol is Bluetooth™ Low Energy (BLE) MAC protocol, maintained by the Bluetooth® Special Interest Group.

In the embodiment, each of AP110and STA120is implemented with an IEEE 802.11 (WLAN or wireless local area network or WiFi™) transceiver (receiver and transmitter) as well as a BLE transceiver (receiver and transmitter). Transmissions and reception of wireless signals using the first protocol are done using the WLAN transceivers, while transmissions and reception of wireless signals using the second protocol are done using the BLE transceivers.

The combined operation of the steps of the flowcharts ofFIG. 2andFIG. 3with wireless device110as AP110, and wireless device120as STA120is described next with reference to timing diagrams.

FIG. 4is a timing diagram illustrating the operations in corresponding blocks (receiver, transmitter, etc.) of AP110and STA120when AP110and STA120communicate with each other according to the flowcharts ofFIG. 2andFIG. 3described above. It is assumed in the description below that each of AP110and STA120contains a WLAN transmitter, a WLAN receiver, a BLE transmitter, and a BLE receiver. The corresponding transmitter/receivers are described in further detail with respect toFIG. 5below.

Waveform410(AP-WLAN-Tx/Rx) represents signal transmissions from, and signal receptions at, the WLAN transmitter of AP110. Waveform420(STA-WLAN-Tx) represents, transmission from the WLAN transmitter of STA120. Waveform430(STA-WLAN-Rx) represents the operational state of the WLAN receiver of STA120, with logic high indicating power ON, and logic low indicating power savings mode. Waveform440(AP-BLE-Tx) represents transmissions from the BLE transmitter of AP110. Waveform450(STA-BLE-Rx) represents the operational state of the BLE receiver of STA120, with logic high indicating power ON, and logic low indicating power savings mode.

It is noted that the waveforms ofFIG. 4are not to scale. Further, the specific sequence of transmission/reception etc., shown inFIG. 4can deviate from that shown there provided the desired effect of reliably powering up the WLAN receiver of STA120to receive the buffered data is ensured.

In the timing diagram ofFIG. 4, it is assumed that STA120has associated and authenticated with AP110sometime prior to t40. During such association, STA120may negotiate with AP110to indicate the capability to operate in power-savings mode (including indicating the ability to receive on BLE receiver and corresponding address information), in accordance with the features of the present disclosure. It is also assumed that, during such negotiation, STA120has synchronized its internal clock with that of AP110, and has provided the frequency as well as start times of beacon transmissions from AP110to the BLE receiver in STA120. As may be readily understood only some of the STAs may have the ability to operate in power-savings mode.

Time intervals t41-t43, t434-t435, etc., (in general logic high intervals) of waveform410represent intervals in which AP110transmits and/or receives WLAN signals (data, control, etc.). AP110may transmit data (for example, directed to other wireless devices such as wireless device150ofFIG. 1) in addition to the periodic beacons (according to WLAN) via the WLAN transmitter in such intervals. The BLE receiver of STA120is shown as being in an ON state when each beacon (e.g., at t41, t434, t44, etc.) is transmitted by AP100, as indicated by the logic high portions of waveform450.

At t42, WLAN transmitter of STA120transmits either a NULL frame or a data frame, with the “Power Management” bit in the “Frame Control” field of the NULL frame or data frame set to one, indicating that the WLAN receiver of STA120is transitioning to power savings mode (step210). AP110receives the indication at, or slightly later, than t42(step310).

At, or slightly later than, t42, the WLAN receiver of STA120is powered-down, as indicated by the logic high to logic low transition of waveform430at t42. It is noted here that several power savings techniques can be used in STA120. For example, power to the entire WLAN receiver (RF plus baseband portions) can be switched off, or power only to the RF portion of WLAN receiver can be switched off. Another technique is to switch-off power to the RF portion of the WLAN receiver, while gating-off the clock to the baseband processing portion. Power savings mode as used herein refers to an operating state of WLAN receiver of STA120, in which the WLAN receiver of STA120is not capable of receiving or processing data.

Sometime between t436and t44, AP110receives data (for e.g., from wireless device150or a device in internet190ofFIG. 1) destined for STA120(step320). AP110locally (internal to AP110) stores/buffers the data. In the traffic indication map (TIM) field of the beacon transmitted at t44, AP110indicates that AP110has data to be transmitted to STA120. In addition, at t45, AP110transmits the same information (i.e., that AP110has data to be transmitted to STA120) from its BLE transmitter, as indicated by the vertical arrow in waveform440(step330). AP110may transmit the information in an appropriate BLE frame, the design of which will be apparent to a skilled practitioner. It is noted that the time instance of transmission through BLE transmitter of AP110is shown as occurring slightly later than t44merely for clarity, and that such transmission can coincide with t44also, or occur even slightly earlier than t44.

Since the BLE receiver of STA120is in power-ON state during (or around, i.e., starting slightly earlier than and ending slightly later than) all beacon transmissions (and therefore during transmission via the BLE transmitter of AP110at t45), the BLE receiver of STA120receives the indication of t45(step220). In response, the BLE receiver of STA120sends a message (internally in STA120) to a processing unit (or some other control unit) in STA120, with the message indicating that data is available to be received by the WLAN receiver of STA120. In response, the processing unit or control unit restores power to the WLAN receiver in STA120. WLAN receiver of STA120transitions to a power-ON state (step230), as indicated by the transition to logic high in waveform430at t46.

At t46, the WLAN transmitter of STA120transmits a power-save poll message (according to WLAN standards) to AP110, as indicated by the vertical arrow in waveform420at t46.

In response to the receipt of the power-save poll message, AP110transmits, at t47, the buffered data destined for STA120to STA120(step340). The WLAN receiver of STA120receives the data (step230), and may process it suitably. The WLAN receiver of STA120may be set again to power savings mode, as indicated by the transition to logic low in waveform430at t48.

With respect to the example described above, it is noted that a BLE receiver typically consumes lesser power than a WLAN receiver. Hence, maintaining the BLE receiver of STA120in a power-ON state to receive data availability indications from AP110, rather than the WLAN receiver of STA120, may effectively reduce power consumption in STA120.

In another embodiment, the BLE receiver of STA120is always (rather than periodically as shown inFIG. 5) maintained in the power-ON state.

In yet another embodiment, BLE receiver of STA120is powered-ON around the end of the listen interval of WLAN receiver of STA120. As is well known in the relevant arts, ‘listen interval’ is a parameter negotiated between an AP and a STA when the STA associates with the AP (before t40), and is represented as a number of beacon periods for which the WLAN receiver of STA will be in power-saving mode. Thus, instead of the WLAN receiver being awake around the end of the listen interval, the BLE receives is turned ON to see if the data indication from AP110would be received. Accordingly, in comparison toFIG. 4, the BLE receiver is not in power ON mode for each beacon interval, but instead would be powered on only once every listen interval. Power consumption is reduced as a result as well.

It is noted here that whether STA120is allowed to place its WLAN receiver in power savings mode, may be controlled by a user/operator/administrator of the wireless network using an input mechanism to STA120, for example in the form of a hard button or soft button (electronic button supported by a touch sensitive interface). A first signal generated by such buttons may indicate that the WLAN receiver can be placed in power savings mode, while a second signal generated by such buttons may indicate that the WLAN receiver is to be operated in active mode only.

Further, an application executing in STA120can also be designed to place the WLAN receiver of STA120in the power savings mode (or active mode) based on the occurrence of an event. An example of such an event (and corresponding signal) can be an indication from peer application (example executing in a device that STA120is in communication with in internet190) that high speed data is going to be sent to STA120via its WLAN receiver. In response to such an indication, STA120maintains its WLAN receiver in active mode to receive the data. Only after completion of receipt of such data, is STA120allowed to (if deemed appropriate) to place its WLAN receiver in power savings mode. Thus, the capability/permission to operate WLAN receiver in power savings mode can be controlled in the manner described above.

The implementation details of a wireless device in an embodiment of the present disclosure are provided next.

5. Example Implementation

FIG. 5is a block diagram showing the implementation details of a wireless device in an embodiment of the present disclosure. Wireless device500may correspond to any of wireless devices110,120and150ofFIG. 1, and is shown containing processing block510, BLE transmitter (Tx)520, BLE receiver (Rx)525, random access memory (RAM)530, real-time clock (RTC)540, battery545, non-volatile memory550, WLAN transmitter (Tx)570, WLAN receiver (Rx)580, switches590and591, and antennas595and596. The combination of WLAN Tx570and WLAN Rx580is referred to herein as a WLAN transceiver. The combination of BLE Tx520and BLE Rx525is referred to herein as a BLE transceiver.

The whole of wireless device500may be implemented as a system-on-chip (SoC), except for battery545and antenna595. Alternatively, the blocks ofFIG. 5may be implemented on separate integrated circuits (IC). When wireless device500represents AP110, wireless device500may additionally contain (though not shown) a network interface to connect to internet190(FIG. 1), as well as input/output blocks for display and user inputs.

Battery545provides power for operation of wireless device500, and may be connected to the various blocks shown inFIG. 5. Although not shown inFIG. 5, wireless device500contains corresponding circuitry (such as power switches, for example) for selectively powering-ON and powering-OFF WLAN Rx580and BLE Rx525(and optionally WLAN Tx570and BLE Tx520also) as described above. RTC540operates as a clock, and provides the ‘current’ time to processing block510.

Antenna595operates to receive from, and transmit to, a wireless medium, corresponding wireless signals according to IEEE 802.11 (WLAN) standards. Switch590may be controlled by processing block510(connection not shown) to connect antenna595to one of blocks570and580as desired, depending on whether transmission or reception of WLAN signals is required. Antenna596operates to receive from, and transmit to, a wireless medium, corresponding wireless signals according to Bluetooth Low Energy (BLE) standards.

Switch591may be controlled by processing block510(connection not shown) to connect antenna596to one of blocks520and525as desired, depending on whether transmission or reception of BLE signals is required. Switches590and591, and antennas595and596, and the corresponding configuration ofFIG. 5are shown merely by way of illustration. A single antenna can instead be used for transmission and reception of WLAN signals, as well as for transmission and reception of BLE signals. Alternatively, a separate antenna can be used for each of WLAN transmission. WLAN reception, BLE transmission and BLE reception. Various other techniques, well known in the relevant arts, can also be used instead.

WLAN Tx570receives data to be transmitted according to WLAN standards and MAC protocol from processing block510, generates a modulated radio frequency (RF) signal according to IEEE 802.11 standards, and transmits the RF signal via switch590and antenna595. WLAN Tx570may contain RF and baseband circuitry for generating and transmitting WLAN signals, as well as for medium access operations. Alternatively, WLAN Tx570may contain only the RF circuitry, with processing block510performing the baseband and medium access operations (in conjunction with the RF circuitry). The transmit portions of waveform410ofFIG. 4correspond to transmissions from WLAN Tx570, when wireless device500represents AP110, and the transmissions of waveform420are performed by WLAN Tx570when wireless device represents STA120.

WLAN Rx580receives an RF signal (according to WLAN standards) bearing data and/or control information via switch590, and antenna595, demodulates the RF signal, and provides the extracted data or control information to processing block510. WLAN Rx580may contain the corresponding RF as well as baseband processing circuitry. Alternatively, WLAN Rx580may contain only the RF circuitry, with processing block510performing the baseband operations in conjunction with the RF circuitry. The receive operations of waveform410are performed by WLAN Rx580, when wireless device500represents AP110. The operational states and receive operations of waveform420correspond to those of WLAN Rx580when wireless device500represents STA120. When wireless device500corresponds to wireless device120/STA120, WLAN Rx580may selectively be powered OFF and powered ON via circuitry such as power switches referred to above. Further, when WLAN Rx580includes baseband processing circuitry, such circuitry may also be selectively powered OFF and powered ON. Alternatively, the master clock provided for operation of such baseband circuitry may be capable of being gated OFF and gated ON by corresponding circuitry.

BLE Tx520receives data to be transmitted according to BLE standards and MAC protocol from processing block510, generates a modulated radio frequency (RF) signal according to BLE standards, and transmits the RF signal via switch590and antenna595. BLE Tx520may contain RF and baseband circuitry for generating and transmitting BLE signals, as well as for medium access operations. Alternatively, BLE Tx520may contain only the RF circuitry, with processing block510performing the baseband and medium access operations (in conjunction with the RF circuitry). The transmission(s) of waveform440ofFIG. 4is/are performed by BLE Tx520when wireless device500represents AP110.

BLE Rx525receives an RF signal (according to BLE standards) bearing data and/or control information via switch590, and antenna595, demodulates the RF signal, and provides the extracted data or control information to processing block510. BLE Rx525may contain the corresponding RF as well as baseband processing circuitry. Alternatively, BLE Rx525may contain only the RF circuitry, with processing block510performing the baseband operations in conjunction with the RF circuitry. The operational states and receive operations of waveform450correspond to those of BLE Rx525when wireless device500represents STA120. When wireless device500corresponds to wireless device120/STA120, BLE Rx580may be implemented with the capability to be selectively powered OFF and powered ON.

Non-volatile memory550is a non-transitory machine readable medium, and stores instructions, which when executed by processing block510, causes wireless device500to operate as described above as wireless device110/AP110and wireless device120/STA120, depending on whether wireless device500represents wireless device110/AP110or wireless device120/STA120. In particular, the instructions enables device500to operate as described with respect to the flowcharts ofFIGS. 2 and 3, when implemented correspondingly.

Processing block510(or processor in general) may contain multiple processing units internally, with each processing unit potentially being designed for a specific task. Alternatively, processing block510may contain only a single general-purpose processing unit. Processing block510may execute instructions stored in non-volatile memory550or RAM530to enable device500to operate according to several aspects of the present disclosure, described above in detail. Processing block510may issue control signals to power-ON/power-OFF WLAN Rx580and BLE Rx525when device500corresponds to wireless device120/STA120. Processing block510may also issue control signals to power-ON/power-OFF WLAN Tx570and BLE Tx520when device500corresponds to wireless device120/STA120.

RAM530is a volatile random access memory, and may be used for storing instructions and data. The data may include the identity of the STAs indicated to have capability to operate in power-savings mode (as described above with respect to negotiation with STAs), and the corresponding parameters (the address of BLE transmitter and BLE receiver for each STA, beacon interval, information required for transmission on BLE transmitter, etc.) such that STAs in the list can be notified of availability of corresponding pending packets, if any, for delivery.

The data also include a list of wireless devices ‘presently’ in power savings mode maintained by wireless device110may be stored in RAM530. When a data unit is received for a STA, processing block510may examine the list to determine whether the data unit is destined to one of the STAs in the list. Processing block510identifies the MAC address of the BLE receiver of STA120(from the above noted data, determined during negotiation), and uses the MAC address to notify (the BLE receiver of STA120) the availability of pending packet for WLAN receiver of STA120.

RAM530and non-volatile memory550(which may be implemented in the form of read-only memory/ROM/Flash) constitute computer program products or machine (or computer) readable medium, which are means for providing instructions to processing block510. Thus, such medium can be in the form of removable (floppy, CDs, tape, etc.) or non-removable (hard drive, etc.) medium. Processing block510may retrieve the instructions, and execute the instructions to provide several features of the present disclosure.