Dynamic power negotiation outside extended beacon exchange in wireless networks via acknowledgement frames - Patents.com

Abstract

An end device (602) in a ZIGBEE communication protocol wireless network includes a memory configured to store computer-executable instructions and a processor coupled to the memory and configured to execute the computer-executable instructions. The processor sends a first data frame (610) to a first network device (604) using a first network transmit power level and receives a first acknowledgment frame (612) from the first network device. The first acknowledgment frame includes a first transmit power information element, the first transmit power information element including a second transmit power level. The processor updates a power control information table entry (628) with the second transmit power level and sends a second data frame to the first network device using the second transmit power level.

Description

[Background technology]

[0001] A wireless network includes two or more electronic devices that communicate with each other via wireless connections. The wireless connections are established using a communication protocol that defines various aspects of the communication between the electronic devices, including, but not limited to, message types, message contents, message formats, messaging sequences, and messaging rules. One example of a communication protocol is the ZIGBEE communication protocol. The ZIGBEE communication protocol is a specification based on the Institute of Electrical and Electronics Engineers (IEEE) 802.15-4. The ZIGBEE communication protocol is designed to create networks with small, low-power digital radios. For example, the ZIGBEE communication protocol can be used to communicate information between electronic devices in home automation systems, wireless sensor networks, industrial control systems, embedded sensing, medical data collection, security systems, building automation, and other types of systems. Summary of the Invention

[0002] In accordance with at least one example, an end device in a ZIGBEE communication protocol wireless network includes a memory configured to store computer-executable instructions and a processor coupled to the memory and configured to execute the computer-executable instructions. The processor sends a first data frame to a first network device using a first network transmit power level and receives a first acknowledgment frame from the first network device. The first acknowledgment frame includes a first transmit power information element, and the first transmit power information element includes a second transmit power level. The processor updates a power control information table entry with the second transmit power level and sends the second data frame to the first network device using the second transmit power level.

[0003] According to another example, a first electronic device in a wireless network is configured to receive a communication message from a second electronic device in the wireless network via a communication link between the first electronic device and the second electronic device, the communication message including a first transmit power level used to transmit the communication message over the communication link, the first electronic device calculates a path loss associated with the communication message by subtracting the first transmit power level from a received signal strength indicator of the communication message, calculates a second transmit power level by subtracting the path loss associated with the communication message from a target received signal strength indicator, and updates a power control information table entry stored in the first electronic device with the second transmit power level.

[0004] According to yet another example, an electronic device is configured to perform an initial transmit power negotiation when joining a wireless network, receive a number of communication messages from a communication link in the wireless network, compare the number of communication messages to a preset number of communication messages, and perform a transmit power renegotiation if the number of communication messages is equal to the preset number of communication messages. [Brief description of the drawings]

[0005] For a detailed description of various examples, reference is now made to the accompanying drawings.

[0006] [Figure 1] 1 is a schematic diagram of a wireless network in accordance with various examples.

[0007] [Diagram 2] 1 is a schematic block diagram of an electronic device in accordance with various examples.

[0008] [Diagram 3]1 is a process flow diagram of a method for controlling power negotiation in a wireless network, in accordance with various examples.

[0009] [Figure 4] 1 is a schematic block diagram illustrating an implementation of initial transmit power negotiation between a network device and a joining device, in accordance with various examples.

[0010] [Diagram 5] 1 is a process flow diagram of a method for determining whether to perform transmit power renegotiation between two network devices, in accordance with various examples.

[0011] [Figure 6] 1 is a schematic block diagram illustrating an implementation of transmit power renegotiation between a transmitting network device and a receiving network device, in accordance with various examples.

[0012] [Figure 7] 1 is a process flow diagram of a method for performing a target power calculation, in accordance with various examples.

[0013] [Figure 8] 1 is a schematic diagram of a transmit power information element in accordance with various examples.

[0014] [Figure 9] 1 is a schematic diagram of a power control interface (PCI) table entry format, in accordance with various examples.

[0015] [Figure 10] 1 is a message flow for dynamic power negotiation in a wireless network, in accordance with various examples.

[0016] [Figure 11]1 is a graph comparing transmit power levels over time for a scenario using static power levels and a scenario using dynamic power negotiation, in accordance with various examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In some communication protocols, the transmission power used to communicate between two electronic devices in a wireless network may be initially determined during a device scanning phase when one of the electronic devices joins the wireless network. If the transmission power is adjusted later, the electronic device may send another message (e.g., a link power delta command) after joining the wireless network to adjust the transmission power with the device with which it is communicating. For example, the electronic device may periodically wake up from a sleep state and send a link power delta command including a full command frame to adjust the transmission power. In such a case, the above transmission power adjustment method may require extra power because the electronic device needs to wake up from a sleep state and send a separate power adjustment message, both of which consume power. This extra power consumption is particularly undesirable in battery-powered electronic devices.

[0018] An example of dynamic power negotiation in a wireless network is described herein. The transmit power used by an electronic device to communicate with another electronic device in a wireless network may be initially determined during a device scanning phase when the electronic device joins the wireless network. The device may also adjust its transmit power later by adding transmit power information to an existing message. For example, a transmit power information element may be added to a media access control (MAC) acknowledgement frame. The transmit power information element may include information about the transmit power used by the electronic device to communicate over the communication link. This information may be used to determine whether the transmit power should be adjusted, and may be used to adjust the transmit power, if necessary. Thus, a separate message is not sent to adjust the transmit power after the electronic device initially joins the wireless network. Instead, the transmit power information is added to an existing message, and a complete separate message is not sent. This also reduces the number of times the electronic device wakes up from a sleep state. Thus, the example of dynamic power negotiation in a wireless network may reduce power consumption. This may be useful in power-sensitive wireless networks, such as wireless networks that use battery-powered devices.

[0019] FIG 1 is a schematic diagram of a wireless network 100 in accordance with various examples. The wireless network 100 includes end devices 102, a router 104, and a coordinator 106. The end devices 102, the router 104, and the coordinator 106 are wirelessly connected by a communication link 108. The wireless network shown in FIG 1 has seven end devices 102 and two routers 104. However, the wireless network 100 may include any number of end devices 102 and routers 104. Additionally, the end devices 102, the routers 104, and the coordinator 106 may be connected using any network topology and are not limited to the particular network topology shown in the example of FIG 1.

[0020] Each end device 102 may be connected to one of the routers 104 or the coordinator 106 via a communication link 108 and may communicate directly only with the router 104 or the coordinator 106 to which it is connected. In some examples, each communication link 108 may be associated with its own transmit power used by the device communicating via that communication link 108. Thus, the communication links 108 may use different transmit powers. The transmit power used for each of the communication links 108 may be determined and / or adjusted using examples of the present description to reduce power consumption. For example, the transmit power used by an electronic device for one of the communication links 108 may be reduced as the distance of one of the communication links 108 is reduced (e.g., as the electronic device moves toward another electronic device that is communicating with one of the links 108). The communication link 108 may operate in a radio frequency band having a frequency less than 1 gigahertz, including, but not limited to, the 700 megahertz band (e.g., 784 megahertz band), the 800 megahertz band (e.g., 868 megahertz band), the 900 megahertz band (e.g., 915 megahertz band), or any other frequency. Also, in some examples, the end device 102 may be a battery-powered low-power device (e.g., a sensor or display). Thus, reducing the amount of power used by the end device 102 reduces the amount of maintenance (e.g., replacing batteries) required to keep the wireless network 100 functioning.

[0021] Each router 104 routes traffic between end devices 102, other routers 104, and the coordinator 106. For example, each router 104 receives and stores messages being sent to end devices 102 connected to the router 104. Each router 104 may also allow new end devices 102 that are not part of the wireless network 100 to join the wireless network 100.

[0022] The coordinator 106 may provide the same functionality as one of the routers 104, and in some examples, the coordinator 106 is the first device to become part of, and thus form, the wireless network 100. The coordinator 106 stores information about the wireless network 100 and may act as a bridge to another network if the wireless network 100 is connected to another network.

[0023] 2 is a schematic block diagram of an electronic device 200, according to various examples. The electronic device 200 may be used as any of the end devices 102, routers 104, and coordinators 106 in the wireless network 100 of FIG. 1. The electronic device 200 may be in a home automation system, a wireless sensor network, an industrial control system, embedded sensing, medical data collection, security systems, building automation, and other types of systems. For example, the electronic device 200 may be a smart hub, a voice assistant, a switch, a thermostat, a motion sensor, a valve, a thermometer, a hygrometer, a smart plug, a window and door sensor, a smoke detector, a light, a siren, a leak detector, or a dimmer.

[0024] The electronic device 200 may include a processor 202, a transceiver 204 coupled to the processor 202, and a memory 206 coupled to the processor 202. The processor 202 is configured to execute computer-executable instructions stored on the processor 202 or in the memory 206 to execute logic and control functions of the electronic device 200. The transceiver 204 may include a wireless radio frequency transmitter and receiver capable of communicating with other electronic devices. In some examples, the transceiver 204 may operate in a radio frequency band having a frequency less than 1 gigahertz (e.g., sub-gigahertz radio). The memory 206 may store computer-executable instructions necessary to implement functions of the electronic device 200. In some examples, the memory 206 may include a non-transitory medium, with instructions (e.g., computer-executable instructions) stored on the non-transitory medium. In such a case, the processor 202 may be configured to execute instructions stored on the non-transitory medium to perform a method (e.g., a method for power negotiation in a wireless network).

[0025] In some examples, memory 206 stores software for implementing the ZIGBEE communication protocol, which is a specification based on IEEE 802.15-4. In such a case, memory 206 may include physical layer software 212, MAC layer software 214, network layer software 216, and application layer software 218. Physical layer software 212 provides electrical, mechanical, and procedural interfaces to the transmission medium. MAC layer software 214 interfaces to physical layer software 212 and controls hardware responsible for interacting with the transmission medium. Network layer software 216 interfaces to MAC layer software 214 and controls message forwarding and routing. Application layer software 218 interfaces to network layer software 216 and specifies communication protocols and interface methods used by devices in the communication network. Memory 206 may also include a PCI table 222 that stores the transmit power used when communicating with other devices. For example, electronic device 200 may store the transmit power used with each other device to which electronic device 200 connects in a wireless network, such as wireless network (FIG. 1).

[0026] FIG. 3 is a process flow diagram of a method 300 for controlling power negotiation in a wireless network, according to various examples. In block 302, an initial transmit power negotiation is performed between an electronic device joining a wireless network and another electronic device that is already part of the wireless network. In some examples, the initial transmit power negotiation is performed when the electronic device joins the wireless network. An example method for performing the initial transmit power negotiation is described below with reference to FIG. 4. In block 304, a transmit power check is performed after the electronic device joins the wireless network. If the transmit power check indicates that a transmit power adjustment is not needed, the electronic device maintains the previously negotiated transmit power in block 306. An example method for performing the transmit power check is described below with reference to FIG. 5. If the transmit power check indicates that a transmit power adjustment is needed, the electronic device performs a transmit power renegotiation in block 308. An example method for performing the transmit power renegotiation is described below with reference to FIG. 6.

[0027] 4 is a schematic block diagram 400 of performing an initial transmit power negotiation between a network device 402 (e.g., a device that is already part of a wireless network) and a joining device 404 (e.g., a device that is attempting to join a wireless network) according to various examples. The joining device 404 generates an extended beacon request message 410 and sends the extended beacon request message 410 to the network device 402. In some examples, the extended beacon request message 410 may be transmitted at the maximum transmit power of the joining device 404 and may include a vendor-specific information element indicating that the joining device 404 supports performing a later power renegotiation process with an acknowledgement message. Although the vendor-specific information element may include two bytes of information, the vendor-specific information element may use any amount of information to indicate that it supports performing a power renegotiation process. After receiving the extended beacon request message 410, the network device 402 calculates a target transmit power for the network device 402 and the joining device 404 to use in communicating on the communication link between the network device 402 and the joining device 404 in block 420. For example, the network device 402 may use a method 700 for performing a target power calculation as shown in FIG. 7 and described below. After the network device 402 calculates the target transmit power, the network device populates a PCI table with the target transmit power in block 422. The network device 402 then generates an extended beacon request message 412 and sends the extended beacon request message 412 to the joining device 404 in block 424. The extended beacon request message 412 may include the target transmit power. Also, in some examples, the extended beacon message 412 may include a vendor-specific information element indicating that the network device 402 supports performing a power renegotiation process at a later time. A vendor specific information element indicative of the network device 402 may be stored by the network device 402 (eg, in a memory of the network device 402 ), retrieved, and added to the extended beacon message 412 .The joining device 404 receives the extended beacon message 412 and enters the target transmit power into its PCI table in block 426. Thus, after the initial transmit power negotiation is performed, the network device 402 and the joining device 404 can use the calculated target transmit power when communicating with each other over their communications link until a new target transmit power is calculated.

[0028] 5 is a process flow diagram of a method 500 for determining whether a transmit power renegotiation needs to occur between two network devices, according to various examples. At block 502, a receiving network device (e.g., a router, such as the router 104 of FIG. 1, or a coordinator, such as the coordinator 106 of FIG. 1, in a wireless network, such as the wireless network 100 of FIG. 1) receives a communication message (e.g., a unicast frame) from a sending network device (e.g., an end device or a router in the wireless network). At block 504, the receiving network device determines the number of communication messages received from the sending network device since the initial power negotiation or power renegotiation between the receiving network device and the sending network device. The receiving network device compares the number to a preset number of communication messages. The preset number of communication messages may be any number of communication messages and may be set by a manufacturer, a vendor, an end user, or any other person or group, or may be determined autonomously based on operating conditions or needs. If the currently received communication messages are less than the preset number of communication messages, no action is taken and the receiving network device and the sending network device continue to use the previously negotiated or renegotiated transmit power in block 506. If the currently received communication messages equal the preset number of communication messages, the receiving network device proceeds to determine whether a received signal strength indicator (RSSI) of the currently received communication messages is within or outside the preset tolerance in block 508.

[0029] The RSSI of the currently received communication message is an estimated power level at which the receiving network device will receive the communication message from the sending network device. In block 508, the receiving network device compares the RSSI of the currently received communication message with the preset RSSI. For example, the preset RSSI may be any RSSI value, set of values ​​(e.g., lower RSSI and higher RSSI), range of values, etc., and may be set by a manufacturer, a vendor, an end user, or any other person or group, or may be determined autonomously based on operating conditions or needs. If the RSSI of the currently received communication message is within the preset RSSI, no action is taken, and the receiving network device and the sending network device continue to use the previously negotiated or renegotiated transmit power in block 506. If the RSSI of the currently received communication message is outside the preset RSSI, the receiving network device recalculates the target transmit power to be used in the communication between the sending network device and the receiving network device in block 510. For example, the receiving network device may use a method 700 for performing a target power calculation, illustrated in FIG. 7 and described below.

[0030] In block 512, the receiving network device compares the recalculated target transmit power with the currently used transmit power. The recalculated target transmit power may be the same as the currently used transmit power. This indicates that the transmit power cannot be changed to a more optimal level. In such a case, no action is required and the receiving network device and the sending network device continue to use the transmit power previously negotiated or renegotiated in block 506. If the recalculated target transmit power is different from the currently used transmit power, this indicates that the transmit power can be changed to a more optimal level. In such a case, the receiving network device performs a transmit power renegotiation in block 514 to change the transmit power used by the sending network device and the receiving network device on the link used for communication between the sending network device and the receiving network device.

[0031] 6 is a schematic block diagram of a transmit power renegotiation 600 between a transmitting network device 602, such as the end device 102 of FIG. 1, and a receiving network device 604, such as the router 104 of FIG. 1, according to various examples. The transmitting network device 602 generates a data frame, at block 608, and sends the data frame to the receiving network device 604, at block 610. The transmit data frame may be sent at a transmit power level currently used by the transmitting network device 602 and the receiving network device 604 for communication on a communication link connecting the transmitting network device 602 and the receiving network device 604. For example, the currently used transmit power level may be a transmit power level calculated when the transmitting network device 602 initially joined the wireless network, or may be a renegotiated transmit power level calculated during a previous renegotiation process. In some examples, the currently used transmit power level is stored in a PCI table of the sending network device 602 and a PCI table of the receiving network device 604 .

[0032] At block 620, the receiving network device 604 determines that a transmit power level renegotiation is necessary. At block 622, the receiving network device 604 calculates new target transmit power levels to be used by the sending network device 602 and the receiving network device 604. For example, the receiving network device 604 may use the method 700 for performing target power calculations, shown in FIG. 7 and described below, to calculate new target transmit power levels to be sent by the sending network device 602 and the receiving network device 604. At block 624, the receiving network device 604 enters the new target transmit power levels into its PCI table, and at block 626, the receiving network device 604 generates an acknowledgement frame to be sent to the sending network device 602. The acknowledgement frame may include an information element (e.g., a transmit power information element) that includes the new target transmit power level. An example of a transmit power information element is shown in FIG. 8 and described below. Thus, a separate message is not sent to adjust the transmission power after the electronic device first joins the wireless network. Instead, the transmission power information is added to the existing message, and a complete separate message is not sent. This also reduces the number of times the electronic device wakes up from a sleep state. Thus, an example of dynamic power negotiation in a wireless network may reduce power consumption.

[0033] Once the receiving network device 604 generates the acknowledgement frame, in block 626, the receiving network device 604 sends the acknowledgement frame 612 to the sending network device 602. The sending network device 602 receives the acknowledgement frame and uses the information in the acknowledgement frame (e.g., the new target transmit power level) to enter into its PCI table, in block 628. For example, the sending network device 602 may replace the transmit power level previously stored in its PCI table with the new target transmit power level. Thus, after the transmit power renegotiation 600 is performed, the sending network device 602 and the receiving network device 604 use the new target transmit power level when communicating with each other.

[0034] 7 is a process flow diagram of a method 700 for performing a target power calculation, according to various examples. At block 702, an extended beacon response is received. The extended beacon response may include a transmit power information element that includes a transmit power of the extended beacon response. At block 704, the transmit power is extracted from the extended beacon response, and an RSSI of the extended beacon response is identified. At block 706, an effective path loss is calculated. In some examples, the effective path loss is calculated using Equation 1. Formula 1: PATHLOSSpwr=EBRRSSI-TXPOWERpwr (1) In Equation 1, PATHLOSSpwr is the effective path loss and may be expressed in units of decibel milliwatts. EBRRSSI is the RSSI of the extended beacon response and may be expressed in units of decibel milliwatts. TXPOWERpwr is the transmit power of the extended beacon response in units of decibel milliwatts.

[0035] Once the effective path loss is calculated, a renegotiated transmit power is calculated at block 708. The renegotiated transmit power may be the transmit power required to overcome the effective path loss. In some examples, the renegotiated transmit power is calculated using Equation 2. Formula 2: EBPWR=OPTRSSI+PATHLOSSpwr (2) In Equation 2, EBPWR is the renegotiated transmit power and may be expressed in units of decibel milliwatts. OPTRSSI is the optimum RSSI and may be expressed in units of decibel milliwatts. PATHLOSSpwr is the effective path loss (e.g., as determined using Equation 1) and may be expressed in units of decibel milliwatts. In some examples, the optimum RSSI may be set to a value that may reduce power consumption without sacrificing signal quality. The optimum RSSI may be set by a manufacturer, vendor, end user, or any other person or group, or may be determined autonomously based on operating conditions as needed.

[0036] Once the renegotiated transmit power is calculated, in block 710, the renegotiated transmit power is sent to the transmitting network device, and in block 712, both the transmitting network device and the receiving network device use the renegotiated transmit power to communicate over the link between the transmitting network device and the receiving network device.

[0037] 8 is a schematic diagram of a transmit power information element 800, in accordance with various examples. The transmit power information element 800 may be added to a frame during initial transmit power negotiation or during transmit power renegotiation. For example, the transmit power information element 800 may be added to an extended beacon request during initial power negotiation or during transmit power renegotiation after initial power negotiation. The transmission power information may be added to the MAC acknowledgement frame. Thus, a separate message is not sent to adjust the transmission power after the electronic device first joins the wireless network. Instead, the transmission power information is added to the existing message, and a complete separate message is not sent. This also reduces the number of times the electronic device wakes up from a sleep state. Thus, the dynamic power negotiation example in the wireless network may reduce power consumption.

[0038] The top line of the transmit power information element 800 indicates a data size 802, and the bottom line of the transmit power element 800 indicates a data type 804. The data size 802 is expressed as a number of octets, where one octet contains 8 bits of information. The data size 802 shown in the transmit power information element 800 is for illustrative purposes only. The data size 802 is not limited to any particular data size.

[0039] The data type 804 includes a power information element header 810, a vendor organization unique identifier 812, a sub-information element descriptor 814, a transmit power 816, and a power information element termination 818. The power information element header 810 may include two octets of information and includes a length, a group identifier, and a type of the transmit power information element 800. The vendor organization unique identifier 812 may include three octets of information and includes a number that uniquely identifies a vendor, manufacturer, or organization. The sub-information element descriptor 814 may include two octets of information and includes a description of the power characteristics. The transmit power 816 may include one octet of information and includes the transmit power currently being used, and the power information element termination 818 may include two octets of information and includes an indication of the termination of the transmit power information element 800.

[0040] 9 is a schematic diagram of a format of a PCI table entry 900, according to various examples. Each device in a wireless network may include a PCI table having an entry, such as PCI table entry 900, for each other device in the wireless network to which the device is connected with a link. The top line of the PCI table entry 900 indicates a data size 902, and the bottom line of the PCI table entry 900 indicates a data type 904. The data size 902 is expressed as a number of octets, with one octet containing 8 bits of information. The data size 902 shown in the PCI table entry 900 is for illustrative purposes only. The data size 902 is not limited to any particular data size and may include any data size.

[0041] The data type 904 includes a short address 910, an IEEE address 912, a transmit power level 914, a last RSSI level 916, and a network layer negotiated flag 918. The short address 910 may include two octets of information and includes a short address of another network device. For example, the short address 910 may be a 16-bit number that uniquely identifies the other network device on the wireless network. The IEEE address 912 may include eight octets of information and includes an IEEE address of the other network device that uniquely identifies the other network device on the wireless network in an IEEE specified format. The transmit power level 914 may include one octet of information and indicates a previously negotiated or renegotiated transmit power level between the network device storing the PCI table entry 900 and the other network device to which the network device is connected using a link. The last RSSI level 916 may include one octet of information and includes the RSSI level of the last communication message received from the other network device. The network layer negotiated flag 918 may include one octet of information, including a flag indicating whether the other network device has joined or rejoined the wireless network. For example, the network layer negotiated flag 918 may be set to "1" indicating that the other network device has successfully joined or rejoined the wireless network, and the network layer negotiated flag 918 may be set to "0" indicating that the other network device has not joined or rejoined the wireless network. In some examples, the network device may periodically (e.g., once every 10 seconds or another pre-configured time interval) check for entries in its PCI table that have the network layer negotiated flag set to "0" and delete the entries.

[0042] 10 is a message flow 1000 for dynamic power negotiation in a wireless network, according to various examples. The message flow 1000 is implemented using a joining device network layer 1002, a joining device MAC layer 1004, a network device MAC layer 1006, and a network device network layer 1008. The joining device network layer 1002 and the joining device MAC layer 1004 may be implemented by a device, such as the end device 102 of FIG. 1, joining a wireless network device, and the network device MAC layer 1006 and the network device network layer 1008 may be implemented by a network device, such as the router 104 of FIG. 1. At step 1010, the joining device network layer 1002 sends an active scan message to the joining device MAC layer 1004. The active scan message may include an extended beacon join message or an extended beacon rejoin message. At step 1012, the joining device MAC network layer 1004 sends an extended beacon request to the joining device MAC layer 1006. The extended beacon request may be sent at the maximum transmit power and may include a transmit power information element. In step 1014, the network device MAC layer 1006 sends a message to the network device network layer 1008 to calculate the link transmit power and update the PCI table entry for the link between the joining device and the network device. In step 1016, the network device MAC layer 1006 sends an extended beacon to the joining device MAC layer 1004. The extended beacon may include a transmit power information element including the calculated link transmit power. In step 1018, the joining device MAC layer 1004 sends an extended beacon indication to the joining device network layer 1002 including the calculated link transmit power, and the joining device network layer 1002 updates the PCI table entry for the link between the joining device and the network device. After step 1018, the joining device and the network device may use the calculated link transmit power when communicating over the link between the joining device and the network device.

[0043] In block 1020, one or both of the joining device and the network device change location, and the path loss between the joining device and the network device changes. Thus, the link transmit power may be renegotiated. In step 1022, the joining device network layer 1002 sends an association request to the joining device MAC layer 1004. In step 1024, the joining device MAC network layer 1004 sends an association request to the network device MAC layer 1006 with the previously calculated link transmit power. In step 1026, the network device MAC layer 1006 recalculates the link transmit power to generate a renegotiated link transmit power, adds a transmit power information element including the renegotiated link transmit power to an acknowledgement frame, updates the PCI table with the renegotiated link transmit power, and sends an association request indication to the network device network layer 1008. In step 1028, the network device MAC layer 1006 sends an acknowledgement frame including the renegotiated transmit power to the joining device MAC layer 1004, which updates the PCI table entry with the renegotiated link transmit power. After step 1028, the joining device and the network device may use the renegotiated link transmit power when communicating over the link between the joining device and the network device.

[0044] After step 1028, the joining device and / or the network device change location again, and the path loss between the joining device and the network device changes. Thus, the link transmit power may be renegotiated once again. In step 1030, the network device MAC network layer 1006 sends an association request with the renegotiated link transmit power to the joining device MAC layer 1004. In step 1032, the joining device MAC layer 1004 recalculates the link transmit power to generate a second renegotiated link transmit power, adds a transmit power information element including the second renegotiated link transmit power to the acknowledgement frame, updates the PCI table with the second renegotiated link transmit power, and sends an association response indication to the joining network device network layer 1002. In step 1034, the joining device MAC layer 1004 sends an acknowledgement frame with the second renegotiated link transmit power to the network device MAC layer 1006, which updates the PCI table entry with the second renegotiated link transmit power. After step 1034, the joining device and the network device may use the second renegotiated link transmit power when communicating over the link between the joining device and the network device.

[0045] FIG. 11 is a graph 1100 comparing theoretical transmit power levels over time for a scenario 1110 using static power levels and a scenario 1112 using dynamic power negotiation. The horizontal or x-axis 1102 represents time in seconds. The vertical or y-axis 1104 represents transmit power in decibel milliwatts. The scenario 1110 using static power levels illustrates an example of transmit power levels that are set when a device (e.g., end device 102 of FIG. 1) joins a wireless network (e.g., wireless network 100 of FIG. 1) and are not subsequently renegotiated, while the scenario 1112 using dynamic power negotiation illustrates an example of transmit power levels when transmit power is dynamically renegotiated after a device joins a wireless network. The scenarios 1110 using static power levels and 1112 using dynamic power negotiation are theoretical examples of power levels. Actual power levels may vary based on the device's environment.

[0046] Scenario 1110 using static power levels and scenario 1112 using dynamic power negotiation both involve a coordinator communicating with a device moving towards it that is initially 10 meters away from the coordinator and moves towards the coordinator at a speed of 1 meter per second for 9 seconds until the device is finally 1 meter away from the coordinator. Scenario 1112 using dynamic power negotiation also uses a target receive power level of -5 dBmilliwatts and a renegotiation period of 3 seconds.

[0047] As seen in FIG. 11, scenario 1110 using static power levels is at a constant transmit power level of −5 dBmW throughout the entire 9 second period displayed in graph 1100. Scenario 1112 using dynamic power negotiation starts at a transmit power level of −5 dBmW. However, as the device moves toward the coordinator, the transmit power level decreases until it reaches a final value of −7 dBmW at the end of the 9 second period. Over the course of the 9 seconds, the transmit power is, on average, 0.532 dBmW less for scenario 1112 using dynamic power negotiation. Thus, scenario 1112 using dynamic power negotiation reduces power consumption compared to scenario 1110 using static power levels.

[0048] The term "couple" is used throughout the specification. This term may encompass any connection, communication, or signal path that allows for a functional relationship consistent with this description. For example, in a first example, device A is coupled to device B if device A generates a signal to control device B to perform a certain action, or in a second example, device A is coupled to device B via an intervening component C such that device B is controlled by device A via a control signal generated by device A, where the intervening component C does not substantially change the functional relationship between device A and device B.

[0049] A device that is "configured to" perform a certain task or function may be configured (e.g., programmed and / or hardwired) at the time of manufacture by a manufacturer to perform that function and / or may be configurable (or reconfigurable) by a user after manufacture to perform that function and / or other additional or alternative functions. Such configuration may be accomplished through firmware and / or software programming of the device, through the construction and / or layout of the hardware components and interconnections of the device, or a combination thereof.

[0050] A circuit or device described herein as including certain components may instead be adapted to be combined with those components to form the described circuit or device. For example, a structure described as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and / or inductors), and / or one or more sources (voltage and / or current sources) may instead include only the semiconductor elements (e.g., a semiconductor die and / or integrated circuit (IC) package) in a single physical device and may be adapted to be combined with at least some of the passive elements and / or sources to form the described structure during or after manufacture, e.g., by an end user and / or a third party.

[0051] Although certain components may be described herein as being of a particular process technology, these components may be substituted for components of other process technologies. Circuits described herein are reconfigurable to include substituted components to provide functionality at least partially similar to that available prior to the substitution of the components. Components shown as resistors generally represent any one or more elements coupled in series and / or parallel to provide the amount of impedance represented by the resistor shown, unless otherwise noted. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in parallel between the same nodes. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in series between the same two nodes as a single resistor or capacitor.

[0052] Use of the phrase "ground voltage potential" in the preceding description includes chassis ground, earth ground, floating ground, virtual ground, digital ground, common ground, and / or any other form of ground connection that is applicable or suitable for the teachings of the present description. Unless otherwise stated, "about," "approximately," or "substantially" preceding a value means ±10 percent of the stated value. Variations in the described examples are possible, and others are possible, within the scope of the claims.

Claims

1. An electronic device, comprising: a memory configured to store computer-executable instructions; a processor coupled to the memory, sending a first data frame to a first network device using a first transmit power level; receiving a first acknowledgment frame from the first network device, the first acknowledgment frame including a first transmit power information element, the first transmit power information element including a second transmit power level; updating a first power control information table entry with the second transmit power level; sending a second data frame to the first network device using the second transmit power level; sending a third data frame to the second network device using a third transmit power level; receiving a second acknowledgment frame from the second network device, the second acknowledgment frame including a second transmit power information element, the second transmit power information element including a fourth transmit power level; updating a second power control information table entry with the fourth transmission power level; sending a fourth data frame to the second network device using the fourth transmit power level; The processor is configured to control operations including:

2. An electronic device comprising:

2. 2. The electronic device of claim 1, The electronic device, wherein the operation further includes storing a power control information table in a memory of the electronic device, the power control information table including the first power control information table entry and the second power control information table entry.

3. 3. The electronic device of claim 2, The electronic device, wherein the power control information table further includes an address, a transmit power level, and a most recent received signal strength indicator for each of the first power control information table entry and the second power control information table entry.

4. 2. The electronic device of claim 1, The electronic device, wherein the first transmit power information element further includes a vendor identifier.

5. 2. The electronic device of claim 1, The operation, making a first determination of a number of communication messages received since a previous power negotiation; comparing the number of communication messages to a preset number of communication messages; calculating a path loss, calculating the second transmit power level, and updating the first power control information table entry in response to the number of communication messages being equal to the preset number of communication messages; The electronic device further comprises:

6. The electronic device of claim 1, An electronic device, wherein the electronic device is configured to operate in an IEEE 802.15.4 based wireless network.

7. The electronic device of claim 6, The electronic device, wherein the electronic device is further configured to operate as an end device in a XIGBEE communication protocol wireless network.

8. 1. An electronic device comprising: a memory configured to store computer-executable instructions; a processor coupled to the memory, receiving a first communication message from a second electronic device in a wireless network over a communication link between the electronic device and the second electronic device, the first communication message including a first transmit power level to be used for transmitting the first communication message over the communication link; calculating a path loss associated with the first communication message by subtracting the first transmit power level from a received signal strength indicator of the first communication message; calculating a second transmit power level by subtracting the path loss associated with the first communication message from a target received signal strength indicator; updating a first power control information table entry stored in the electronic device with the second transmit power level; transmitting an acknowledgement message in response to the first communication message, the acknowledgement message including a first transmit power information element that includes the second transmit power level; making a first determination of a number of communication messages received since a previous power negotiation; comparing the number of communication messages to a preset number of communication messages; calculating the path loss, calculating the second transmit power level, and updating the first power control information table entry in response to the number of communication messages being equal to the preset number of communication messages; The processor is configured to control operations including:

2. An electronic device comprising:

9. 9. The electronic device of claim 8, The electronic device, wherein the wireless network comprises a ZIGBEE communication protocol wireless network.

10. 9. The electronic device of claim 8, The electronic device, wherein the first transmit power information element further includes a vendor identifier.

11. 10. The electronic device of claim 9, a coordinator configured to operate in the ZIGBEE communication protocol wireless network; The second electronic device comprises an end device operating in the ZIGBEE communication protocol wireless network.

12. The electronic device of claim 8, The electronic device, wherein the first communication message includes an extended beacon response.

13. The electronic device of claim 12, The operation, extracting the first transmit power level from the extended beacon response; identifying the received signal strength indicator as the extended beacon response received signal strength indicator; The electronic device further comprises:

14. The electronic device of claim 8, The electronic device, wherein the operations further include sending a third communication message using the second transmit power level.

15. The electronic device of claim 8, The electronic device, wherein the previous power negotiation is an initial power negotiation.

16. The electronic device of claim 15, the operations further include joining the wireless network; The initial power negotiation is performed when the electronic device joins the wireless network.

17. The electronic device of claim 16, The electronic device, wherein the wireless network is an IEEE 802.15.4 based wireless network.

18. The electronic device of claim 8, the operations further include determining whether the received signal strength indicator is outside an acceptable range in response to the number of communication messages being equal to the preset number of communication messages; The electronic device, wherein calculating the second transmit power level includes calculating the second transmit power level in response to the received signal strength indicator being outside an acceptable range.

19. The electronic device of claim 8, The electronic device, wherein the operations further include transmitting a second communication message using the first transmit power level before receiving the first communication message.

20. The electronic device of claim 19, The electronic device, wherein the first communication message comprises a data frame.

21. The electronic device of claim 8, The electronic device, wherein the first power control information table entry includes an address associated with the second electronic device, the second transmit power level, and the received signal strength indication.

22. The electronic device of claim 8, the operations further include storing in the memory a power control information table including the first power control information table entry and a second power control information table entry; The electronic device, wherein the power control information table further includes an address, a transmit power level, and a last received signal strength indication for each of the first power control information table entry and the second power control information table entry.

23. The electronic device of claim 8, The electronic device, wherein the first communication message is a unicast message.

24. 1. An electronic device comprising: a memory configured to store computer-executable instructions; a processor coupled to the memory, performing an initial transmit power negotiation when joining a wireless network; receiving a number of communication messages from a communication link in the wireless network; comparing the number of communication messages to a preset number of communication messages; performing a transmit power renegotiation when the number of the communication messages is equal to a preset number of the communication messages; The processor is configured to control operations including:

2. An electronic device comprising:

25. 24. The electronic device of claim 23, The operation, comparing a received signal strength indicator of a communication message immediately preceding said communication message received over said communication link with a preset received signal strength indicator; performing the transmit power renegotiation in response to a received signal strength indicator of a communication message immediately preceding the communication message not being within the preset received signal strength indicator; The electronic device further comprises:

26. 24. The electronic device of claim 23, The operation, comparing the recalculated target transmit power with the currently used transmit power; performing the transmit power renegotiation in response to the recalculated target transmit power being different from the currently used transmit power; and The electronic device further comprises:

27. 24. The electronic device of claim 23, The electronic device, wherein the communication message includes a unicast frame from a sending network device.

28. 28. The electronic device of claim 27, The electronic device, wherein the sending network device comprises an end device.

29. 28. The electronic device of claim 27, The electronic device, wherein the sending network device comprises a router.

30. 24. The electronic device of claim 23, The operation, calculating a renegotiated transmit power level; updating a power control information table entry stored in said electronic device with said renegotiated transmission power level; The electronic device further comprises:

31. 30. The electronic device of claim 29, The electronic device, wherein the operations further include transmitting another communication message over the communication link in the wireless network using the renegotiated transmit power level.

32. The electronic device of claim 24, performing the transmit power renegotiation, determining a first transmit power level; updating a power control information table entry with the first transmission power level; transmitting an acknowledgment message in response to a communication message of the communication messages, the acknowledgment message including a first transmit power information element that includes the first transmit power level; 2. An electronic device comprising:

33. The electronic device of claim 31, The electronic device, wherein the operations further include transmitting another acknowledgment message not including a transmit power information element in response to the number of communication messages not being equal to the preset number of communication messages.

34. An electronic device comprising: a memory configured to store computer-executable instructions; a processor coupled to the memory, receiving a first communication message from a second electronic device in a wireless network over a communication link between the electronic device and the second electronic device, the first communication message including a first transmit power level to be used to transmit the first communication message over the communication link; calculating a path loss associated with the first communication message by subtracting the first transmit power level from a received signal strength indicator of the first communication message; calculating a second transmit power level by subtracting the path loss associated with the first communication message from a target received signal strength indicator; updating a first power control information table entry stored within the electronic device with the second transmit power level; transmitting an acknowledgement message in response to the first communication message, the acknowledgement message including a first transmit power information element that includes the second transmit power level; receiving a second data frame; determining whether to renegotiate a transmit power level; transmitting a second acknowledgment message not including a transmit power information element in response to determining not to renegotiate the transmit power level; The processor is configured to control operations including:

2. An electronic device comprising:

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