Patent Application
20160112311
1. Technical Field
Embodiments of the present disclosure relate generally to wireless local area networks (WLAN), and more specifically to providing enhanced connectivity to end devices via access points of WLANs.
2. Related Art
Wireless local area networks (WLAN) are implemented in conformity with IEEE 802.11 family of standards, and provide connectivity via wireless communication medium. End devices refer to source or destination of each packet transmitted on WLANs.
End devices often rely on an access point (AP) for communication with other devices in the WLAN, in which case the WLAN is said to operate in infrastructure BSS mode). APs operate as wireless nodes forwarding each packet until the packet is delivered to the corresponding destination device. Thus when two end devices are connected via the same AP, that AP operates to forward each packet from one of the end devices to the other, and vice versa.
There is a general need to provide enhanced connectivity to end devices via APs of WLANs. For example, it is often desirable that packets be exchanged between an end device associated with one AP and another end device associated with another AP. It may also be desirable that the wireless devices be able to exchange packets with devices connected via Internet as well.
Example embodiments of the present invention will be described with reference to the accompanying drawings briefly described below.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.
1. Overview
A wireless node of a wireless network maintains link information for a set of layer-2 addresses, each of the layer-2 addresses corresponding to a medium access control (MAC) address of a corresponding device that transmits packets on the wireless network. The link information indicates whether the corresponding device is in an uplink direction or a downlink direction with respect to the wireless node. The wireless node receives a layer-2 packet in one of the uplink direction and downlink directions, the layer-2 packet containing a layer-2 address specifying a destination system, with no layer-2 address in the layer-2 packet indicating that the packet is destined to the wireless node. The wireless node forwards the layer-2 packet to a next wireless device in one of the uplink direction and downlink direction.
In an embodiment, receipt, at the wireless node, of a DHCP packet enables the wireless node to add the link information in relation to the source system from which the DHCP packet originates.
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.
Internet 150 extends the connectivity of end devices to various systems (not shown) connected to Internet 150. Internet 150 may 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. AP 190 operates as an access point in accordance with 802.11 standards, and routes packets to/from Internet 150, in addition to operating as a Dynamic Host Configuration Protocol (DHCP) server to assign IP addresses to various end devices and wireless nodes, as described in sections below. AP 190 is connected to internet 150 on wired path 195.
End devices 110 and 120 are sources or destinations of various packets. End devices 110 and 120 are shown associated (by corresponding dotted lines) with respective wireless nodes 160 and 170 (operating as APs of corresponding WLANs) in accordance with 802.11 standards. The end device from which a packet originates is referred to as a ‘source system’, while the end device to which a packet is eventually delivered is referred to as a ‘destination system’.
Wireless nodes 160, 170 and 180 (together forming a wireless network) forward packets in accordance with features of the present disclosure to provide enhanced connectivity to end devices 110 and 120. During each hop between a pair of wireless nodes, the transmitting wireless node is referred to as a ‘transmitter’, while the receiver of the packet is referred to as a ‘receiver’. In the first hop, the source system is thus the transmitter. In the last hop, the destination system is the receiver.
End devices 110 and 120, and wireless nodes 160, 170 and 180, and AP 190 together form a wireless mesh network, with AP 190 being the root node of the wireless mesh network. In general, a wireless mesh network is a network in which one or more corresponding wireless nodes/end devices of the wireless mesh network operate to forward packets from another wireless/node/end device until the packet reaches a destination system. The destination system may be an end device within the wireless mesh network itself, or be a device external to the wireless mesh network, such as for example a device (not shown) connected via internet 150. Each of end devices 110 and 120 is capable of operating in power savings mode according to IEEE 802.11 standard.
The flow of packets towards AP 190 is termed as uplink direction, and towards end stations from AP 190 is termed as downlink direction. The operation of each of the wireless nodes is described in sections below. All devices of
According to an aspect of the present disclosure, each of wireless nodes 160, 170 and 180 maintains link information that enables the corresponding wireless node to route packets to the appropriate next hop device in the uplink or downlink direction, and the manner in which such link information is created is described next with respect to a flowchart.
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 step 201, in which control immediately passes to step 210.
In step 210, wireless node 180 receives a packet in the uplink direction with a source address equaling layer-2 address of a source system. As also noted above, the term uplink direction as used herein refers to the direction of packet transfer (or packet movement) from a corresponding device/component of
In step 230, wireless node 180 forwards the packet with no address equaling the self-layer 2 address, and with source address equaling the layer-2 address of source system. The word ‘self’ implies that the layer-2 address is of the same wireless node 180, by which step 230 is performed. Thus, neither the header portion nor the payload portion in the packet forwarded by wireless node 180 contains the layer-2 address of wireless node 180. As described below, in an embodiment, the address of the source system is continued to be transmitted across each hop in the uplink direction. Control then passes to step 240.
In step 240, wireless node 180 updates (or creates if not yet created) the link information to indicate that an end device with the source address of the packet is present in the downlink direction (i.e., in the direction from which the packet is received). Link information refers to information that enables wireless node 180 to appropriately process a packet received from a source system, and may include the layer-2 address of the source system, direction of presence (downlink/uplink) with respect to wireless node 180, the next-hop address to which the packet received from the source system should be forwarded, encryption/decryption keys to be used, etc. Control then passes to step 210, and the steps of the flowchart may be repeated again (for example for another end node in the downlink direction).
In an embodiment of the present disclosure, the steps of the flowchart of
Once each of wireless nodes 160, 170 and 180 is populated with link information of end nodes 110 and 120, as well as of the corresponding wireless nodes in the downlink direct, the wireless nodes participate in exchange of data (information) packets (e.g., in the form of unicast, multicast or broadcast packets) between the corresponding end device and one or more devices in internet 150 or with another end device.
According to an aspect of the present disclosure, a wireless node spoofs layer-2 addresses of one or more other devices (end devices and/or other wireless nodes in the downlink direction). The term “spoofing” as used herein refers to a wireless node either forwarding a packet with the layer-2 address of the spoofed device in the header of the packet (rather than that of the wireless node itself), and picking and processing a packet on the air (wireless medium) that has the destination layer-2 address of the spoofed device (rather than that of the wireless node). In addition, the wireless node sets up and maintain an association according to IEEE 802.11 standards between a spoofed device and the corresponding wireless node.
With the layer-2 addresses of the corresponding device in the downlink direction thus spoofed, a wireless node may participate in exchange of data packets between the spoofed device and either another spoofed device or a device in internet 150, as illustrated next with respect to the flowchart of
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 step 301, in which control immediately passes to step 310.
In step 310, wireless node 180 maintains link information indicating layer-2 addresses being spoofed, and the direction (uplink or downlink) in which the node with the corresponding address is present. The link information may be created in the manner described above with respect to the steps of the flowchart of
In step 320, wireless node 180 receives a layer-2 packet destined to a destination system, with no layer-2 address indicating that the packet is directed to the wireless node. Thus, the packet received by wireless node 180 does not contain the (self) layer-2 address of wireless node 180. Control then passes to step 330.
In step 330, wireless node 180 identifies the layer-2 address in the packet corresponding to the destination system. Wireless node 180 may inspect the destination address field in the received layer-2 packet to identify the layer-2 address of the destination system. Control then passes to step 350.
In step 350, wireless node 180 determines if the identified address has an entry in the maintained link information. If the identified address has an entry in the maintained link information, control passes to step 360. However, if the identified address does not have an entry in the maintained link information, control passes to step 370. For purposes of step 350, a layer-2 broadcast address is deemed to have an entry, requiring the packet to be forwarded in the appropriate direction(s).
In step 360, wireless node 180 drops the packet, i.e., wireless node 180 does not further process or forward the packet. Control then passes to step 320, in which wireless node 180 may receive another layer-2 packet, and the corresponding steps of the flowchart may be repeated.
In step 370, wireless node 180 forwards the packet to the next wireless device in the direction indicated by the identified entry. Forwarding implies that the data bits constituting the packet are transmitted again on the wireless medium to the next wireless device. In case of a broadcast packet, the packet is forwarded in all directions (including the uplink direction, assuming the packet is received from one of the end devices), except the direction in which the packet is received. Control then passes to step 320, in which wireless node 180 may receive another layer-2 packet, and the corresponding steps of the flowchart may be repeated.
The features described above with respect to
In an embodiment of the present disclosure, each of wireless nodes 160, 170 and 180 of
Each AP/STA combination may either have separate physical radio interfaces (one radio for AP and another for STA) or have a single radio (single transmit and receive processing chains for both AP and STA). The AP and STA in a wireless node are termed to be operating in the ‘concurrent mode’ when there is time division multiplexing between the AP and STA operations. It is assumed in the representation of
A user may provision the corresponding STA in wireless nodes 160, 170 and 180 to associate with corresponding APs. In an embodiment, the provisioning of STAs (e.g., 162, 172 and 182) in wireless nodes is such as to set-up a linear topology of the wireless nodes. In other embodiments of the present disclosure however, provisioning may be done so as to create other types of topologies (such as for example a tree topology). The topology of wireless nodes shown in
End devices 110 and 120 (which are also wireless stations or STAs) are assumed to be associated respectively with AP 161 and AP 171, and the respective associations are shown by dotted lines 116 and 127. The combination of an AP and the associated STAs represents an infrastructure basic service set (BSS) according to IEEE 802.11 standards. An AP and the associated STA(s) may cooperatively generate a security key using known techniques (e.g., WPA2 of IEEE 802.11), and each AP and STA is assumed to possess a security key for encryption and decryption of packets.
Each of APs 161, 171 and 181 may operate consistent with the definition of an access point in IEEE 802.11 standards. Thus, APs 161, 171 and 181 may transmit beacons at corresponding intervals, buffer data for STAs associated with them to enable the STAs to transition to power-saving mode/stat, etc. Each of STAs 162, 172 and 182 may operate consistent with the definition of a wireless station (STA) in the infrastructure mode of IEEE 802.11 standards. Thus, the STAs may associate with the corresponding APs, transition to power-saving states, etc.
According to an aspect of the present disclosure, after provisioning, a corresponding device (AP or STA or end device) broadcasts a DHCP request packet for being assigned an IP address, and receipt of a DHCP request packet at a wireless node is the basis for creating link information in the wireless node. A DHCP request packet may be forwarded via the corresponding AP/STA paths (according to the associations provisioned) to the DHCP server in AP 190, and an assigned IP address may be provided in the return path to the requesting device. When the DHCP requester is STA 182, no forwarding is required, since STA 182 is already associated with AP 190 and can request for an IP address directly.
The packet formats and address conventions of packets (including DHCP request packets and data/information packets) used in an embodiment of the present disclosure are briefly described next.
Frame Control 510 internally contains several fields for specifying various frame control parameters such as protocol version, To DS, From DS, Power Management, etc. According to the IEEE 802.11 standards, a logic zero in each of the To DS and From DS fields (row 1 in table 595) signifies that the frame is being transmitted from one wireless station (STA) of an independent BSS (IBSS or ad hoc network) to another wireless station of the IBSS, or is a control or management frame. A logic one in each of the To DS and From DS fields (row 4 in table 595) signifies that the frame is being transferred from one AP to another AP in a wireless distribution system (WDS). A logic zero entry in the To DS field and a logic one entry in the From DS field (row 2 in table 595) signifies that the frame is being transmitted from an AP to a wireless station in an infrastructure BSS. A logic one entry in the To DS field and a logic zero entry in the From DS field (row 3 in table 595) signifies that the frame is being transmitted from a wireless station to the corresponding AP in an infrastructure BSS.
Table 595 of
In an embodiment of the present disclosure the address convention of row 2 of
The manner in which a DCHP request from a device in the downlink direction is used to create or update link information maintained at each of wireless nodes 160, 170 and 180 is described next with examples.
6. DHCP Broadcasts and Creation of Link Information
According to an aspect of the present disclosure, each STA of a wireless node spoofs the layer-2 address of every device in the downlink direction with respect to the STA. Thus, a packet forwarded by a STA in the uplink direction always contains the layer-2 address of the spoofed device (rather than that of the STA itself). Thus, STA 182 is designed to spoof layer-2 addresses for AP 181, STA 172, AP 171, end device 120, STA 162, AP 161 and end device 110. STA 172 spoofs layer-2 addresses for AP 171, end device 120, STA 162, AP 161 and end device 110. STA 162 spoofs layer-2 addresses for AP 161 and end device 110.
Due to such layer-2 address spoofing by STA of a wireless node, the source address (address_2 in row 3 of table 595 of
To illustrate, after being provisioned (i.e., after association with AP 161), end device 110 broadcasts a DHCP request packet, with Address_1530 equal to BSSID of AP 161, Address_2540 equal to its own layer-2 (MAC) address, and Address_3550 containing FFFF (hexadecimal). FFFF (hexadecimal) in Address_3550 field indicates that the packet is a broadcast packet. The corresponding fields (such as the contents of Frame Body 580) of the packet may contain data specifying that the packet is a DHCP request packet. AP 161 forwards the packet (with the required changes in the packet) to STA 162 on a path internal to wireless node 160.
STA 162 on receipt of the DHCP request packet determines that end device 110 is present in the downlink direction (based on Address_2540, which is the address of the source system, here end device 110), and creates link information entries including layer-2 address of end device 110, direction of presence (downlink), and the next-hop address (here AP 171, since STA 162 is associated with AP 171). STA 162 forwards the DHCP request packet to AP 171, with the forwarded packet containing BSSID of AP 171 in the Address_1530 field, layer-2 (MAC) address (spoofed) of end device 110 in Address_2540 field, and FFFF (hexadecimal) in Address_3550 field. AP 171 forwards (with no modification to the packet) the received packet to STA 172 on a path internal to wireless node 170.
STA 172 on receipt of the DHCP request packet determines that end device 110 is present in the downlink direction (based on Address_2540, which is the address of the source system, here end device 110), and creates link information entries including layer-2 address of end device 110, direction of presence (downlink), and the next-hop address (here AP 181, since STA 172 is associated with AP 181). STA 172 forwards the DHCP request packet to AP 181, with the forwarded packet containing BSSID of AP 181 in the Address_1530 field, layer-2 (MAC) address (spoofed) of end device 110 in Address_2540 field, and FFFF (hexadecimal) in Address_3550 field. AP 181 forwards (with no modification to the packet) the received packet to STA 182 on a path internal to wireless node 180.
STA 182 on receipt of the DHCP request packet determines that end device 110 is present in the downlink direction (based on Address_2540, which is the address of the source system, here end device 110), and creates link information entries including layer-2 address of end device 110, direction of presence (downlink), and the next-hop address (here AP 190, since STA 182 is associated with AP 191). STA 182 forwards the DHCP request packet to AP 190, with the forwarded packet containing BSSID of AP 190 in the Address_1530 field, layer-2 (MAC) address (spoofed) of end device 110 in Address_2540 field, and FFFF (hexadecimal) in Address_3550 field.
In response to the forwarded DHCP request from STA 182, AP 190 transmits an IP address for end device 110 in a packet, with the destination address in the packet being set to the MAC address of end device 110. Since STA 182 spoofs the layer-2 link between end device 110 and AP 190, STA 182 processes the packet even though none of the address fields in the packet contains the MAC address of STA 182. STA 182 forwards the packet to AP 181. The packet is forwarded in the downlink direction till it is delivered to end device 110.
In the illustration provided above, each of STAs 162, 172 and 182 may additionally store the corresponding security key used for the spoofed link. In other words, a corresponding security key is stored for each spoofed link.
DHCP requests from the other devices present in the downlink direction are similarly processed, with the link information for each device being created and stored locally in the STAs of the corresponding wireless nodes after receipt of the corresponding DHCP request packet. Since STA 182 is associated (due to provisioning by a user) with AP 190, STA 182 obtains an IP address from the DHCP server in AP 190 by sending a DHCP request packet to AP 190. The IP addresses assigned by AP 190 are such that all of wireless nodes 160, 170, and 180, and end devices 110 and 120 are in the same IP subnet, with AP 190 being the edge router for the subnet. While IP addresses are noted as being assigned based on DHCP requests, IP addresses may also be assigned statically. In such a case, the link information described above may be populated when ARP broadcasts are sent (instead of DHCP broadcast) by the end devices.
Thus, STA 182 spoofs layer-2 addresses for AP 181, STA 172, AP 171, end device 120, STA 162, AP 161 and end device 110. AP 181 also creates link information entries specifying which next-hop address a packet received at AP 181 should be forwarded to, and the corresponding security key to be used for encryption or decryption (depending on whether a packet is to be transmitted or a received packet is to be processed), etc.
STA 172 spoofs layer-2 addresses for AP 171, end device 120, STA 162, AP 161 and end device 110. STA 162 spoofs layer-2 addresses for AP 161 and end device 110. The link information stored for such spoofing is described below.
The entry ‘any’ in column 651 indicates that the source address can be that of any of the devices in the uplink direction with respect to the device/interface in column 650. For example, in row 613, the source address 651 can be that of any of STA 182 and AP 190. The entry ‘any’ in column 652 indicates that the destination address can be that of any of devices in the uplink direction with respect to the device/interface in column 650. For example, in row 617, the destination address 652 can be that of any of STA 182 and AP 190. The entry ‘any’ in the other tables of
In table 600 of
Rows 607 through 611 list the corresponding entries for the columns 650-656 when STA 182 receives a packet whose sources are respectively AP 161, STA 162, AP 171, STA 172 and AP 181. Row 612 list the entries when STA 182 is the source of a packet. Although not shown in table 600, STA 182 would forward the corresponding packet to AP 190 with the source address field in the packet containing the layer-2 (MAC) address of the corresponding (spoofed) source, as noted above.
Rows 613 through 616 list the corresponding entries for the columns 650-656 when AP 181 receives a packet whose destinations are respectively AP 161, STA 162, AP 171 and STA 172. Rows 617 through 621 list the corresponding entries for the columns 650-656 when AP 181 receives a packet whose sources are respectively AP 161, STA 162, AP 171, STA 172 and AP 181.
The same convention as for the entries of the rows and columns in
It may be observed from
Again, it may be observed from
It may be observed from
With the link information thus created, end devices 110 and 120 may exchange data (information) packets with each other and/or with one or more devices in internet 150. It is noted that exchange of packets between end devices 110 and 120 (in general, between any pair of nodes of
Communication between an end device and one or more devices in internet 150 may require IP to enable routing of the packet beyond AP 190 (i.e. within internet 150). Accordingly, packets destined to devices in internet 150 and originating from either end device 110 or 120 (or the other nodes of
To send an IP packet on Internet, end device encapsulates the IP packet with layer-2 header according to row 3 of
When an IP packet is received, AP 190 may examine a local table, which maps the destination IP address of the packet to a corresponding layer-2 address. The IP packet is encapsulated with a layer-2 header in accordance with row 2 of the Table of
An entry corresponding to each device may be formed in the local table (though not shown) as the first packet (e.g., DHCP) is received from that device. Alternatively, ARP type protocols may be employed by AP 190 to ascertain the corresponding layer-2 address. Thus, end devices are provided connectivity via IP protocol also.
The description is continued with respect to the manner in which each layer-2 link can be made secure.
It is noted here that in addition to spoofing a layer-2 address of a device, each of the STAs 162, 172 and 182 establish an association (as defined in the IEEE 802.11 standards) between a spoofed device and a corresponding AP. Thus, for example, STA 182 may establish (separate) associations with AP 190 for each of AP 181, STA 172, AP 171, end device 120, STA 162, AP 161 and end device 110 (total of seven separate associations, in addition to an association between STA 182 itself and AP 190).
For each association, a single/same security key (for both encryption and decryption at the corresponding ends) is maintained in wireless node 180. Since STA 182 maintains eight associations with AP 190 (seven spoofed associations and one for itself), a total of eight security keys are maintained and used by STA 182. The eight keys are KS 161, KS 162, KS 171, KS 172, KS 181, KS 182 (which are listed in
Thus, referring to
Since a total of six associations are maintained by STA 172 with AP 181 (five spoofed associations and one for itself), a total of six security keys are maintained and used by STA 172. The six keys are K3161, K3162, K3171, K3172 (which are listed in
Similarly, since a total of three associations are maintained by STA 162 with AP 1711 (two spoofed associations and one for itself), a total of three security keys are maintained and used by STA 162. The three keys are K2161 and K2162 (which are listed in
The description is continued with an illustration of the internal functional blocks of a wireless node in an embodiment of the present disclosure.
Communication block 930 performs transmit and receive processing operations in wireless node 900. Communication block 930 may receive a packet on a wireless medium via antenna 950. Communication block 930 forwards the packet, on path 913, to AP functionality block 910 if the BSSID field (Address_1530) equals the MAC address of the AP (AP functionality block 910) of wireless node 900. Communication block 930 forwards the packet, on path 923, to STA functionality block 920 if the Address_2540 field contains the BSSID of the AP to which the STA (STA functionality block 920) of wireless node 900 is associated. Communication block 930 may receive packets from AP functionality block 910 and STA functionality block 920, and transmit the packets on the wireless medium via antenna 950.
Link information table 940 contains layer-2 link information created, maintained and updated by wireless node 900. Thus, for example, when wireless node 900 represents wireless node 180, link information table 940 represents table 600, the details of which are shown in
AP functionality block 910 performs the AP functions of wireless node 900. Thus, for example, when wireless node 900 represents wireless node 180 (
AP functionality block 910 may receive a packet from STA functionality block 920 on path 914, and determine if the destination system for the packet is AP functionality block 910 or not If the destination system is AP functionality block 910, AP functionality block 910 may suitably process the packet. Otherwise, AP functionality block 910 performs a look-up of link information table 940 to determine the next-hop address for the packet, form the packet headers correspondingly (address fields, etc.), encrypt the packet with the corresponding encrypt key, and provide the packet to communication block 930 for transmission via antenna 950.
STA functionality block 920 performs the STA functions of wireless node 900. Thus, for example, when wireless node 900 represents wireless node 180 (
STA functionality block 920 may receive a packet from AP functionality block 910 on path 914, and determine if the destination system for the packet is STA functionality block 920 or not If the destination system is STA functionality block 920, STA functionality block 920 may suitably process the packet. Otherwise, STA functionality block 920 performs a look-up of link information table 940 to determine the next-hop address for the packet, form the packet headers correspondingly (address fields, etc.), encrypt the packet with the corresponding encrypt key, and provide the packet to communication block 930 for transmission via antenna 950.
Each of AP functionality block 910 and STA functionality block 920 may receive DHCP requests from other devices (in the downstream direction), and create/update link information table 940 in the manner described above in detail. Although not shown in
The description is continued with an illustration of the hardware implementation of a wireless node, in an embodiment of the present disclosure.
The components/blocks of wireless node 1000 are shown merely by way of illustration. However, wireless node 1000 may contain more or fewer components/blocks. Further, although not shown in
Input block 1060 enables user inputs on path 1062 to be provided to wireless node 1000. Input block 1060 may be provided in the form of a keypad. Output block 1020 enables wireless node 1000 to provide outputs (received on path 1021) to a user, and may be provided in the form of a display unit.
Antenna 1095 (which is equivalent to antenna 950 of
Transmit block 1070 receives data to be transmitted on path 1071 from processing block 1010, generates a modulated radio frequency (RF) signal according to IEEE 802.11 standards, and transmits the RF signal via wireless node 1090 and antenna 1095. Receive block 1080 receives an RF signal bearing data via wireless node 1090, path 1098 and antenna 1095, demodulates the RF signal, and provides the extracted data to processing block 1010 on path 1081.
RTC 1040 operates as a clock, and provides the ‘current’ time to processing block 1010 on path 1041. RTC 1040 may be backed-up by battery 1045 (in addition to the normal source of power, not shown in the Figure). Although not shown as such in
Non-volatile memory 1050 is a non-transitory machine readable medium, and stores instructions, which when executed by processing block 1010, causes wireless node 1000 to operate as described above. The instructions include those that implement AP functionality block 910 and STA functionality block 920 described with respect to
Processing block 1010 (or processor in general) may contain multiple processing units internally, with each processing unit potentially being designed for a specific task. Alternatively, processing block 1010 may contain only a single general-purpose processing unit. Processing block 1010 may execute instructions stored in non-volatile memory 1050 or RAM 1030 to enable wireless node 1000 to operate according to several aspects of the present disclosure, described above in detail.
RAM 1030 is a volatile random access memory, and may be used for storing instructions and data. Thus, the relevant tables of
RAM 1030 and non-volatile memory 1050 (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 block 1010. Thus, such medium can be in the form of removable (floppy, CDs, tape, etc.) or non-removable (hard drive, etc.) medium. Processing block 1010 may retrieve the instructions (via corresponding paths 1051 and 1031), and execute the instructions to provide several features of the present disclosure.
References throughout this specification to “one embodiment”, “an embodiment”, or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present invention should not be limited by any of the above-described embodiments, but should be defined only in accordance with the following claims and their equivalents.
