WO2017095365A1

WO2017095365A1 - Long and short range mode switching

Info

Publication number: WO2017095365A1
Application number: PCT/US2015/062923
Authority: WO
Inventors: Wessam Afifi Ahmed; Enrico-Henrik Rantala; Esa Juhani Tuomaala; Sayantan Choudhury; Mika Kasslin; Jarkko Kneckt; Janne Marin; Olli Alanen
Original assignee: Nokia Technologies Oy; Nokia Usa, Inc.
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2017-06-08

Abstract

Various implementations described herein are directed to a method for communications. The method may receive, by an apparatus, a first management signal indicating a time for a transmission of a second management signal corresponding to a first communication mode. The method may determine whether or not the apparatus was able to decode the second management signal. If the apparatus was able to decode the second management signal, the method may prevent the apparatus from transmitting a signal on a busy tone slot. If the apparatus was not able to decode the second management signal, the method may transmit the signal on the busy tone slot to indicate a request to communicate using a second communication mode.

Description

LONG AND SHORT RANGE MODE SWITCHING

BACKGROUND

[01] Increasing demand for wireless services and higher data rates result in ever increasing requirements for communication efficiency and wireless spectrum use over different ranges. Wireless networks that may be configured to communicate with a number of different types of wireless devices at different positions are one type of wireless network in which such improvements are needed.

BRIEF SUMMARY

[02] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the various embodiments, nor is it intended to be used to limit the scope of the claims.

[03] A recipient device (RD), such as an access point, may be configured to communicate with sender devices (SDs) that are in one of two or more modes. For example, the RD may be configured to communicate with an SD in a long range mode and a short range mode. The RD may allocate a transmission opportunity for devices communicating via long range transmissions, which may be referred to as a check long range transmission opportunity. If the RD detects a signal in the transmission opportunity, the RD may transmit a long range management signal to the device, such as a beacon. The SD may periodically determine whether short range communications can be maintained with the RD, and the SD may remain in the long range mode or enter the short range mode based on the determination. [04] As described above, the RD may transmit management signals, such as a long range management signal. The RD may transmit contiguous management signals, a noncontiguous, or partitioned, management signal, or combinations thereof. For example, the RD may transmit contiguous management signals and non-contiguous management signals periodically, where the non-contiguous management signals are transmitted more frequently than the contiguous management signal. The RD may rank portions of the management signal, and transmit the portions, i.e., noncontiguous management signals, at intervals determined based on the rankings. The RD may transmit the contiguous management signal at a set interval.

[05] Other aspects are discussed further below.

BRIEF DESCRIPTION OF THE DRAWINGS

[06] Certain embodiments are illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements and in which:

[07] Figure 1 illustrates a diagram of an example communication system in which one or more embodiments may be implemented.

[08] Figure 2 illustrates a diagram of device ranges according to one or more embodiments described herein.

[09] Figure 3 illustrates a spectrum use diagram according to one or more embodiments described herein.

[10] Figure 4 illustrates a spectrum use diagram of a short range mode and a long range mode according to one or more embodiments described herein. [11] Figure 5 illustrates a state diagram of a recipient device according to one or more embodiments described herein.

[12] Figure 6 is a flow diagram of a method for long range and short range communications according to one or more embodiments described herein.

[13] Figure 7 illustrates a table for recording connection status according to one or more embodiments described herein.

[14] Figure 8 illustrates a state diagram of a sender device according to one or more embodiments described herein.

[15] Figure 9A is a flow diagram of a method for communicating in a plurality of modes according to one or more embodiments described herein.

[16] Figure 9B is a flow diagram of a method for communicating in a first or second communication mode according to one or more embodiments described herein.

[17] Figure 10 is a flow diagram of a method for transmitting management signals according to one or more embodiments described herein.

[18] Figure 11 illustrates a diagram of management signal transmissions according to one or more embodiments described herein.

[19] Figure 12 illustrates a table of management signal rankings according to one or more embodiments described herein.

[20] Figure 13 illustrates a block diagram of an example communication device according to one or more embodiments described herein.

DETAILED DESCRIPTION [21] In the following description of various illustrative embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments in which aspects described herein may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the described aspects and embodiments.

[22] A recipient device (RD) and a sender device (SD) may communicate via wireless communications. For example, an access point may communicate with a station in a wireless local area network, such as a device in a Basic Service Set (BSS) in IEEE 802.11 based technologies. For example, the RD may be an access point and the SD may be a station. The RD and the SD may communicate in one of a plurality of modes. In one implementation, the RD and the SD may communicate in either a long range mode or a short range mode. For example, in the long range mode the recipient device may communicate in a smaller portion of a spectrum than in the short range mode. In another implementation, an RD may be configured to communicate in only a long range mode or only a short range mode. Compared to the short range mode, the long range mode may be less spectrum efficient but may be able to communicate with devices that are further away, i.e., have a better range. In another implementation, the RD and the SD may communicate in a long range mode, a middle range mode, and a short range mode.

[23] SDs or RDs may comprise low power devices, such as wearable devices, that use wireless networks (e.g., Wi-Fi based networks) to transmit and receive data. These low power devices may be referred to as narrow band (NB) devices, or NB stations. NB devices may have limited power budgets. Thus, it may be desirable to minimize operations for NB devices that are in an awake state to conserve power. For example, an NB device may comprise a sensor, and it may be desirable to conserve power so that the NB device is replaced or recharged less frequently. In one implementation, an NB device may communicate on a subchannel (e.g., a 2 MHz subchannel). For example, the subchannel may be an Orthogonal Frequency-Division Multiple Access (OFDMA) subchannel. In this implementation, the NB device may coexist with devices operating on a channel (e.g., 20 MHz channels). The devices operating on the channel may be referred to as legacy devices. The above bandwidth values are examples, and are not intended to be limiting. In other embodiments, subchannel bandwidth may have a value within range 0.1 MHz...5 MHz, and channel bandwidth may have a value within a range 4 MHz...80 MHz, as examples.

[24] In one embodiment, a term "channel" refers to a frequency resource in a frequency spectrum. The channel may be a channel for a wireless local area network according to IEEE 802.11 technologies. The channel may be a frequency resource covering a certain bandwidth, e.g., 20 Mhz. A term "subchannel" refers to a frequency resource within the channel. The subchannel may cover a subband of the channel bandwidth. As an example, if the bandwidth of the channel is 20 MHz, the channel may comprise 10 subchannels, each of the subchannels having a bandwidth of 2 MHz.

[25] In one implementation, the RD may be configured to communicate with devices that are in a legacy mode, a long range NB mode, and/or a short range NB mode. The RD may determine whether it should operate in the long range mode or short range mode based on signals received from SDs communicating with the RD. For example, if one or more of the SDs communicating with the RD is operating in a long range mode, then the RD may operate in a long range mode. [26] Figure 1 is a diagram of an example communication system in which one or more embodiments may be implemented. As seen in figure 1, a network 100 may include multiple RDs (e.g., access points) 130 and 131 and a number of SDs (e.g., wireless stations) 105, 110, 115, 120, 140, and 150.

[27] The SD 150 may comprise a gateway device, such as a smart phone device, that communicates with a wearable device 140. In one implementation, the wearable device 140 may communicate with the SD 150 over a long range mode or short range mode as described in figures 6, 9A, and 9B. The wearable device 140 may be an NB device. NB devices may use OFDMA subchannels (e.g., sub-20 MHz OFDMA subchannels) to transmit, receive, and listen. For example, the wearable device 140 may use a 2 MHz wide OFDMA subchannel. In this example, the maximum bandwidth of a subchannel may be a multiple of 2 MHz, though other bandwidths are possible. In one implementation, the connection between the SD 150 and wearable device 140 may form a Body Area Network (BAN). The SD 150 may act as an access point for communications between the SD 150 and the wearable device 140. The SD 150 may also act as a sender device for communications between the SD 150 and the RD 131. Data transmitted from the wearable device 140 may be communicated to and stored local in an SD, such as the SD 150, or in a cloud system (e.g., remote data storage accessible over a network). The wearable device 140 may comprise sensors, a processor, such as a microprocessor, and a radio, such as a Wi-Fi radio or Bluetooth Low Energy (BLE) radio. Although the device 140 is described as a wearable device, it should be understood that other types of devices may be used, such as devices that might not be wearable (e.g., devices that comprise the Internet of things (IoT), such as home automation devices (e.g., Internet connected alarm system, garage door opener, sprinkler system, etc.), or devices that implement machine to machine (M2M) technologies, such as cargo tracking devices, etc.). For example, the wearable device 140 may comprise an on-body, off-body, or in-body sensor.

[28] Each RD may be associated with a plurality of SDs to form a group of devices that communicate together (e.g., an independent or infrastructure basic service set (BSS)). For example, RD 130 and SDs 110 and 120 may form a first communication group (i.e., a first BSS) and RD 131 and SDs 105, 115, and 150 may form a second communication group (i.e., a second BSS). While the RD of each communication group may cover different geographical areas (e.g., basic service areas (BSAs)), the communication groups may also cover some common locations such that the communication groups are overlapping (e.g., overlapping BSS (OBSS)). For overlapping communication groups, an SD may be associated with one RD, but be within communication range of another RD such that it could switch from the first communication group to the second communication group. While devices may be described herein as a sender device or a recipient device for convenience, such devices may be capable of bi-directional data transmissions and may include transceivers as opposed to just transmitters or receivers. These devices described as sender devices and recipient devices may switch roles to operate as recipient devices and sender devices respectively to support other data transactions in various embodiments (e.g., downlink transmissions from an access point to a station, broadcast transmissions from a central device to multiple remote devices, etc.).

[29] Figure 2 illustrates a diagram 200 of device ranges according to one or more embodiments described herein. In the diagram 200, SDs 210-214 are positioned at various distances from the RD 130 located at the center of the diagram. SDs 211, 212, and 214 are within a short enough range from the RD 130 that they may communicate with the RD 130 in a short range mode. SDs 210 and 213 are positioned further away from the RD 130, and may communicate with the RD 130 in a long range mode. The SDs 210 and 213 might not be able to communicate with the RD 130 via short range communications because of the distance between the SDs 210 and 213 and the RD 130. For example, the distance may be greater than a threshold distance for short range communications. If the SDs 210 or 213 were to be moved closer to the RD 130, then the SD that moved closer could transition to a short range mode and communicate with the RD 130 via short range communications. Also, if one of the SDs 211, 212, or 214 were to move further from the RD 130, then the SD that moved further could transition to a long range mode to maintain communications with the RD 130 via long range communications. In one implementation, the SDs 210-214 may be NB devices. Although figure 2 illustrates a short range region and a long range region, any number of modes and regions may be used for communications between SDs and RDs.

[30] Figure 3 illustrates a spectrum use diagram 300 according to one or more embodiments described herein. Short range transmission 310 is an example of a transmission emitted by at least one SD or at least one RD operating in a short range mode. The short range transmission 310 may comprise multiple NB transmissions that are cascaded in the frequency domain. For example, each NB transmission in the short range transmission 310 may comprise a 2 Mhz subchannel, and the total channel bandwidth may comprise 20 Mhz. The NB transmissions of the short range transmission 310 may be transmitted by a single transmitter, i.e., an SD or RD, or by a plurality of transmitters, i.e., a plurality of SDs. [31] Long range transmission 320 is an example of a transmission emitted by an SD or an RD operating in a long range mode. For example, the SDs 211, 212, and 214 may communicate with the RD 130 using short range transmissions 310, and the SDs 210 and 213 may communicate with the RD 130 using long range transmissions 320. In one implementation, when an RD is operating in a long range mode, the RD may also occasionally transmit short range transmissions 310. In one implementation, when an RD is operating in a short range mode, the RD may occasionally also transmit long range transmissions 310. These implementations may enable SDs of both short range mode and long range mode to maintain synchronization and/or association with the RD.

[32] In the diagram 300, the long range transmission 320 comprises a single transmission having a 2 Mhz subchannel width or other bandwidth less than the full 20 MHz channel width. In one implementation the long range transmission 320 may be a same or similar amount of power as the total amount of power emitted during the short range transmission 310. In this implementation, the long range transmission 320 may have more power concentrated in a smaller frequency range. For example, a same or similar amount of power may be used for the 2 Mhz wide long range transmission 320 and the 20 Mhz wide short range transmission 310. By concentrating power in a smaller frequency range, the long range transmission 320 may have a longer range, i.e., be capable of being received at a greater distance, than the short range transmission 310. In one implementation, a number of subchannels used during long range transmissions may be one.

[33] In an embodiment, a number of subchannels used when operating in a first communication mode is greater than a number of subchannels used when operating in a second communication mode. If communications on the first communication mode and communications on the second communication mode are configured to be performed according to a same maximum allowed transmission power, then communications on the second communication mode may cover a larger geographic area than communications on the first communication mode. Thus, the second communication mode may be configured to communicate over a longer distance than the first communication mode. For example, the maximum allowed transmission power may be defined by a regulatory domain. This is because communications performed based on the maximum allowed transmission power concentrated in a smaller frequency bandwidth may be decodable farther from the transmitter when compared to communications performed based on the maximum allowed transmission power concentrated in a larger frequency bandwidth. Therefore, in an embodiment, the first communication mode may be referred to as a short range communication mode or short range transmission mode and the second communication mode may be referred to as a long range communication mode or long range transmission mode. In such an embodiment, the short range boundary in Fig. 2 between the short range mode and the long range mode may be the distance at which a short range communication between the SD and RD is decodable by the receiving device. While this boundary is illustrated as a circle in figure 2 (assuming the same signal attenuation in all directions), various embodiments may have irregular short range boundaries due to different attenuations in different directions (e.g., due to structures, geography, environment, etc.).

[34] The long range transmission 320 may be less spectrum efficient than the short range transmission 310 because the long range transmission 320 may use only a portion of the spectrum used by the short range transmission 310. Thus, more information may be transmitted in a period of time by the short range transmission 310 than the long range transmission 320. Although the short range transmission 310 is illustrated as being 20 Mhz wide, and the long range transmission 320 is illustrated as being 2 Mhz wide, various embodiments include transmissions 310 and 320 having other widths. For example, the transmissions 310 and 320 could be 16 Mhz, 8 Mhz, 4 Mhz, or any other width.

[35] Figure 4 illustrates a diagram 400 of a short range mode and a long range mode transmissions according to one or more embodiments described herein. First, a short range management signal 410 is transmitted. For example, the short range management signal may be a beacon having a width of 20 Mhz. The short range management signal 410 may comprise a management signal that is contiguous in frequency. For example, the short range management signal 410 may comprise a plurality of fields, and the fields may be contiguous in frequency, i.e., distributed among a plurality of subchannels. The short range management signal 410 may be transmitted periodically.

[36] In diagram 400, a check long range transmission opportunity 420 occurs after the short range management signal 410. During the check long range transmission opportunity 420, SDs may transmit signals to indicate that they are operating in long range mode. For example, an SD may transmit a busy tone (BT) signal in a busy tone slot during the check long range transmission opportunity 420 to indicate that the SD is operating in long range mode. An SD may transmit the BT signal in response to receiving the short range management signal 410. During the check long range transmission opportunity 420, an RD may monitor the frequency range of the check long range transmission opportunity 420 to determine whether any SDs are operating in long range mode. In the illustrated check long range transmission opportunity 420, no signals were transmitted by an SD or received by the RD.

[37] Long range indicators 440-42 may comprise a transmission that indicates one or more target wait times (TWTs) for short range management signals 411-13. The long range indicators 440-42 may be a periodic narrowband transmission. The long range indicators 440-42 may comprise a media access control (MAC) frame having a MAC header, a frame body with one or more TWTs of short range management signals, and a frame check sequence (FCS) field.

[38] In one implementation, the long range indicators 440-41 may refer to upcoming short range management signals, such as short range management signal 412, based on the short range management signal being followed by a check long range transmission opportunity. In this implementation, the long range indicators 440-42 might not refer to short range management signals that are not followed by a check long range transmission opportunity, such as short range management signals 411 and 413. In another implementation, the long range indicators 440-42 may refer to upcoming short range management signals 411-13 regardless of whether the short range management signals 411-13 are followed by check long range transmission opportunities. In certain variations of this implementation, the long range indicators 440-42 may indicate, for each TWT, whether or not the short range management signal 411-13 corresponding to that TWT will be followed by a check long range transmission opportunity.

[39] Short range management signal 412 is followed by a check long range transmission opportunity 430. During the check long range transmission opportunity 430, two signals (represented in the diagram 400 by the letter 'X') are received. The signals received during the check long range transmission opportunity 430 indicate that two SDs are communicating in long range mode.

[40] In one implementation, the signals received by an RD during the check long range transmission opportunity 430 may correspond to a correlatable sequence. In this implementation, the RD may be able to remove the correlatable sequence from any noise or interference. For example, the correlatable sequence may be used to reduce or eliminate the detection of false positives. False positives may occur when an RD detects that signals were transmitted during a check long range transmission opportunity 430, but no SDs transmitted BTs during the check long range transmission opportunity 430. In another implementation, the RD that receives the signals during the check long range transmission opportunity 430 may compare an energy level of the signals to a threshold energy level, in order to determine whether at least one SD transmitted signals during the check long range transmission opportunity 430. In this implementation, the RD might not determine a number of SDs that transmitted signals during the check long range transmission opportunity 430. The threshold energy level may be a preset or predetermined energy level.

[41] After determining that at least one SD is communicating in long range mode, a long range contiguous management signal 450 may be transmitted. The long range contiguous management signal 450 may be contiguous in time. In one implementation, the long range contiguous management signal 450 may be an NB beacon. Although the illustrated long range contiguous management signal 450 is contiguous, in some implementations only a portion of the long range management signal 450 may be transmitted. Figure 10, further described below, describes a method for transmitting portions of a management signal. [42] An amount of time between sequential short range management signals, e.g., between

410 and 411, 411 and 412, and 412 and 413, may be referred to as a short range management signal interval. The short range management signal interval may be constant or may change. For example, an amount of time between signals 410 and

411 may be shorter than an amount of time between signals 411 and 412. An amount of time between the indicators 440-42 may be referred to as an indicator interval. The indicator interval may be constant or may change. An amount of time between check long range transmission opportunities 420 and 430 may be referred to as a check long range transmission opportunity interval.

[43] It should be understood that the diagram 400 illustrates an exemplary order of signals.

The signals illustrated in the diagram 400 may be transmitted in a different order or at different frequencies. In one implementation, a check long range transmission opportunity may occur after every short range management signal. In an alternative implementation, a check long range transmission opportunity may occur after some but not all short range management signals. In another implementation, indicators 440-42 may be transmitted less frequently than short range management signals.

[44] The sequence and interval of the messages illustrated in the diagram 400 may be determined by an RD. In one implementation, the sequence of the messages or the intervals may be determined by the RD based on statistics or real-time updates regarding the number of devices connected to the RD, the traffic load of the RD, or other parameters. In another implementation, the timing of the various illustrated transmissions may be based on a known communication time of a device. For example, an SD may transmit data at a same time every hour or every day or other periodic time interval, and the RD may know this time and schedule transmissions accordingly.

[45] Figure 5 illustrates a state diagram 500 of a recipient device according to one or more embodiments described herein. The state diagram 500 may correspond to an RD configured to communicate with NB devices. The state diagram 500 may correspond to an RD implementing method 600, described in figure 6. The RD may be in either the short range mode 510 or long range mode 520. While in the short range mode 510, an RD may remain in the short range mode 510 when no transmissions are detected in a check long range transmission opportunity. For example, after the check long range transmission opportunity 420 the RD may remain in the short range mode 510. When a transmission is detected in a check long range transmission opportunity, then the RD may enter long range mode 520. For example, after the check long range transmission opportunity 430, the RD may transition from the short range mode 510 to the long range mode 520.

[46] When the RD is in the long range mode 520, the RD may determine whether any SDs communicating with the RD are in long range mode. For example, the RD may check an association table to determine whether the association tables contains one or more long range identifiers. The long range identifiers may indicate that an SD is communicating with the RD via long range transmissions. If the RD determines that an SD is communicating with the RD via long range transmissions, the RD may remain in long range mode. If the RD determines that no SDs are communicating with the RD via long range transmissions, then the RD may transition from the long range mode 520 to the short range mode 510. [47] While the RD is in long range mode 520, the RD may communicate using both long range transmissions and short range transmissions. In certain variations, when the RD is in short range mode 510, the RD is restricted from communicating via long range transmissions. For example, while in the long range mode 520, the RD may transmit both short range management signals 410-413 and long range management signal 450. In this example, while in the short range mode 510, the RD might not transmit the long range management signal 450.

[48] Figure 6 is a flow diagram of a method 600 for long range and short range communications according to one or more embodiments described herein. In one or more embodiments, the method 600 or one or more steps thereof may be performed by one or more computing devices or entities. For example, portions of the method 600 may be performed by components of the device 1312, described in figure 13, or one or more of the devices 105-50, described in figure 1. The method 600 or one or more steps thereof may be embodied in computer-executable instructions that are stored in a computer-readable medium, such as a non-transitory computer-readable medium. The steps in method 600 might not all be performed in the order specified and some steps may be omitted or changed in order.

[49] At step 605 a device may be in short range mode. For example, an RD 130 or 131 may be in the short range mode 510.

[50] At step 610, periodic check long range transmission opportunities may be allocated.

For example, in figure 4, a time, such as a TWT, for check long range transmission opportunities 420 and 430 may be indicated in the long range indicators 440-42. The frequency range of the check long range transmission opportunity may be preset or may be transmitted. [51] At step 615, after a check long range transmission opportunity, it may be determined whether a transmission was detected during the check long range transmission opportunity. For example, an RD 130 or 131 may determine whether a signal, e.g., a BT, was transmitted by an SD during the check long range transmission opportunity. In one implementation, the energy level received during the check long range transmission opportunity may be compared to a threshold energy level. The threshold energy level may be preset, so that a detected energy level above the threshold corresponds to a determination that a signal has been received during the check long range transmission opportunity. In another implementation, correctable codes may be detected during the check long range transmission opportunity.

[52] If a transmission is not detected during the long range transmission opportunity, then the method 600 may continue to step 605. Thus, if no transmission is detected during the long range transmission opportunity, the device may remain in short range mode.

[53] If a transmission is detected during the long range transmission opportunity, the method 600 may continue to step 620. At step 620, the device enters the long range mode. For example, at step 620, the device may enter the long range mode 520 in response to detecting a transmission in the check long range transmission opportunity.

[54] At step 625, a long range contiguous management signal may be transmitted. For example, the long range management signal 450 may be transmitted at step 625. In one implementation, a long range NB beacon may be transmitted at step 625.

[55] At step 630, one or more long range non-contiguous management signals may be transmitted. Non-contiguous management signals are further described below in figures 10-12. In one implementation, steps 625 and 630 may be performed repeatedly and in any order. It should be understood that step 630 is optional. For example, a device might not transmit non-contiguous management signals. In this example, the device may transmit only long range contiguous management signals.

[56] At step 635 it may be determined whether communications are being maintained with any devices in long range mode. For example, table 700, described below, may be maintained by an RD and analyzed by the RD to determine whether any devices are communicating with the RD via long range communications.

[57] If no devices are communicating via long range communications, the method 600 may proceed to step 605. For example, if an SD is communicating with an RD via long range communications, but then the SD is moved closer to the RD, the SD may transition from long range mode to short range mode, and the RD may transition from long range mode to short range mode in response to the SD communicating via short range communications.

[58] If it is determined that one or more devices are continuing to communicate via long range communications, the method 600 may proceed to step 620 and remain in long range mode. As described above, while in the long range mode, communications may be maintained with devices that are in short range mode and with devices that are in long range mode.

[59] Figure 7 illustrates a table 700 for recording connection status according to one or more embodiments described herein. The table 700 is an example of a table that might be maintained by an RD or another device to record data regarding SDs connected to the RD. The first column of the table 700 indicates an ID for each SD connected to the RD. The ID may be assigned by the RD, or provided by the SD. The second column of the table 700 indicates an address of each RD connected to the SD. For illustrative purposes, the addresses in figure 7 correspond to the reference numbers used in figure 2. In one implementation, the address in figure 7 might be an IP address or a MAC address of an SD.

[60] The third column of the table 700 indicates a time to live (TTL) of each SD connected to the RD. The TTL may indicate an amount of time until an SD is disassociated from the RD if no signals are received, by the RD, from the SD. The TTL may be based on a threshold amount of time for inactivity, such as a preset or predetermined threshold amount of time. For example, if the SD is inactive for a period of time greater than the threshold amount of time, the RD may remove the SD from the table 700.

[61] The fourth column of the table 700 indicates a long range indicator. In one implementation, the long range indicator may comprise one bit. In the table 700, the fourth column indicates that the SDs 210 and 213 are in long range mode and the SDs 211, 212, and 214 are in short range mode. If an RD is in the long range mode 520, and the table 700 does not indicate that there are any SDs communicating with the RD, then the RD may enter the short range mode 510.

[62] Figure 8 illustrates a state diagram 800 of a sender device according to one or more embodiments described herein. The state diagram 800 may correspond to an NB SD, such as one of the SDs 105, 110, 115, 120, 140, or 150. The state diagram 800 may correspond to an SD implementing method 900, described below in figures 9A and 9B. The SD may be in either a short range mode 810 or long range mode 820. While in the short range mode 810, the SD may communicate with an RD via short range transmissions. The SD may remain in the short range mode 810 while short range management signals are decodable. For example, if the short range management signals 410-13 can be decoded by the SD, then the SD may remain in the short range mode 810.

[63] If a short range management signal cannot be decoded by the SD, the SD may transition to the long range mode 820. For example, if the SD 211, as illustrated in figure 2, is moved from the short range region to the long range region, then the SD 211 might not receive the short range management signal and thus may transition from the short range mode 810 to the long range mode 820. While in the long range mode 820, the SD may communicate with the RD via long range transmissions. While the short range management signals transmitted by the RD cannot be decoded by the SD the SD may remain in the long range mode 820. If the SD can decode one of the short range management signals, then the SD may transition back to short range mode 810. For example, if the SD 210, as illustrated in figure 2, is moved from the long range region to the short range region, then the SD 210 may transition from the long range mode 820 to the short range mode 810.

[64] Figure 9A is a flow diagram of a method 900 for communicating in a plurality of modes according to one or more embodiments described herein. In one or more embodiments, the method 900 or one or more steps thereof may be performed by one or more computing devices or entities. For example, portions of the method 900 may be performed by components of the device 1312, described in figure 13, or one or more of the devices 105-50, described in figure 1. The method 900 or one or more steps thereof may be embodied in computer-executable instructions that are stored in a computer-readable medium, such as a non-transitory computer-readable medium. The steps in method 900 might not all be performed in the order specified and some steps may be omitted or changed in order.

[65] At step 905, a long range indicator may be received. For example, the long range indicator 440 may be received. The long range indicator may comprise an NB beacon or a portion of the NB beacon. The long range indicator may indicate a scheduled time for a short range management signal, such as one of the short range management signals 410-13. For example, the scheduled time for the short range management signal may be a TWT. In one embodiment, the scheduled time may comprise a scheduled start time for transmitting the short range management signal. In another embodiment, the scheduled time may comprise both a scheduled start time and a scheduled duration for transmitting the short range management signal.

[66] At step 910, a device may optionally wake at the indicated time for the short range management signal and attempt to receive, i.e., listen for, the short range management signal. For example, one of the short range management signals 410-13 may be received at step 910.

[67] At step 915, the short range management signal may be decoded, if received. If the short range management signal is decodable, then the method may return to step 910 and wait for the next scheduled short range management signal. Returning to step 910 may correspond to entering or remaining in the short range mode 810. In one embodiment, entering or remaining in the short range mode 810 may comprise transmitting and receiving frames according to short range mode before receiving a next scheduled short range management signal. [68] If the short range management signal is not detected or decodable at step 915, the method may proceed to step 920. In one implementation, if the short range management signal is not decodable at step 915, a device may be prevented from transmitting a signal during a busy tone slot, such as during a check long range transmission opportunity. For example, if the short range management signal is not received at step 915, then the method may proceed to step 920. Proceeding to step 920 from step 915 may correspond to entering the long range mode 820. At step 920, a check long range transmission opportunity may be accessed. For example, a BT signal may be transmitted during a busy tone slot, such as a check long range transmission opportunity. The check long range transmission opportunity may be accessed in response to failing to decode the short range management signal.

[69] At step 925 a counter may be initialized. For example, a counter maintained by an SD may be initialized to zero and started. At step 930, one or more long range management signals may be received, and the counter may be incremented in response to receiving a long range management signal. For example, the long range management signal 450 may be received at step 930. The management signal received at step 930 may be contiguous or non-contiguous. For example, a portion of the long range management signal 450 may be received at step 930.

[70] At step 935 it may be determined whether the counter value is greater than a threshold. The threshold may be a preset or predetermined value. If the counter is not greater than the threshold, the device may remain in long range mode and return to step 930.

[71] If the counter is greater than the threshold, the counter may be reset or deactivated at step 940. Then, at step 945, the device may wake at a scheduled time to attempt to receive a short range management signal. The scheduled time may have been communicated in a long range indicator or in long range management signal. Actions performed at step 945 may be similar to those performed at step 910. At step 950, it may be determined whether the short range management signal is detected or decodable. Actions performed at step 950 may be similar to those performed at step 915.

[72] If the short range management signal is not decodable at step 950, the method 900 may return to step 925. For example, if the short range management signal is not decodable at step 950, the device may remain in the long range mode 820.

[73] If the short range management signal is decodable at step 950, the method 900 may proceed to step 955. In response to successfully decoding the short range management signal at step 950, the device may transition from the long range mode 820 to the short range mode 810. At step 955, a signal may be transmitted indicating that the device is entering the short range mode 810.

[74] Figure 9B is a flow diagram of a method 960 for communicating in a first or second communication mode according to one or more embodiments described herein.

[75] At step 960, a first management signal may be received. The first management signal may indicate a time for a second management signal, where the second management signal corresponds to a first communication mode. For example, the first communication mode may be a short range mode. The first management signal may comprise a long range indicator, such as the long range indicator 440. The second management signal may comprise a short range management signal, such as the short range management signals 410-13. In one implementation, the first management signal indicates a time for a busy tone slot. The time for the busy tone slot may be subsequent to the time for the second management signal. Actions performed at step 960 may be similar to those described above at step 910.

[76] At step 965, it may be determined whether the second management signal is detected or decodable. For example, it may be determined whether or not a computing device is able to decode, or receive at the time indicated in the first management signal, the second management signal. Actions performed at step 965 may be similar to those described above at step 915.

[77] If the management signal is found to be decodable at step 965, transmission of a signal during a busy tone slot may be prevented at step 970. Alternatively, if the management signal is not found to be decodable at step 965, the signal during the busy tone slot may be transmitted, at step 975, on the busy tone slot to indicate a request to communicate using a second communication mode. The busy tone slot may comprise a check long range transmission opportunity. Actions performed at step 975 may be similar to those described above at step 920.

[78] After transmitting the signal on the busy tone slot at step 975, a third management signal corresponding to the second communication mode may be received. For example, the third management signal may comprise the contiguous long range management signal 450. In one implementation, the third management signal may comprise a plurality of contiguous management signals. After receiving the third management signal, a plurality of other management signals that are smaller than the third management signal may be received. The plurality of other management signals might not be contiguous in time. [79] Figure 10 is a flow diagram of a method 1000 for transmitting management signals according to one or more embodiments described herein. In one or more embodiments, the method 1000 or one or more steps thereof may be performed by one or more computing devices or entities. For example, portions of the method 1000 may be performed by components of the device 1312, described in figure 13, or one or more of the devices 105-50, described in figure 1. The method 1000 or one or more steps thereof may be embodied in computer-executable instructions that are stored in a computer-readable medium, such as a non-transitory computer-readable medium. The steps in method 1000 might not all be performed in the order specified and some steps may be omitted or changed in order.

[80] At step 1010, transmissions may be detected in a check long range transmission opportunity. Actions performed at step 1010 may be similar to actions performed at step 615, described above.

[81] At step 1020 a management signal may be transmitted in a contiguous manner. The contiguous management signal may comprise a beacon. The contiguous management signal may be generated by an RD and may comprise information to be used by an SD maintaining a wireless connection with the RD. The management signal transmitted at step 1020 may comprise an NB signal, such as a long range NB signal.

[82] At step 1030, portions of the management signal may be ranked. Figure 12, discussed below, illustrates an example of a ranking for portions of the management signal. In one implementation, the portions may be ranked based on the type of information in the content signal. For example, the portions may be ranked based on how critical or important the portion of the management signal is to an SD. In a second implementation, the portions may be ranked based on how often information within each portions changes or is estimated to change. For example, a static portion of the management signal may be given a low ranking, whereas a portion of the management signal that changes frequently may be given a higher ranking.

[83] At step 1040 an interval may be assigned to each rank. The interval for a rank may correspond to a frequency at which the portions of the management signal corresponding to that rank are transmitted. For example, a portion of the management signal that is more static, such as information describing supported rates, may be given a longer interval, and thus have a lower frequency than a portion of the management signal that changes frequently, such as synchronization signals.

[84] At step 1050, an interval may be assigned to the contiguous management signal. The interval assigned at step 1050 may be longer than all or a portion of the intervals assigned at step 1040.

[85] At step 1060 portions of the management signal, i.e., a non-contiguous management signal may be transmitted, as well as the contiguous management signal, based on the intervals assigned at steps 1050 and 1040. In some implementations, the contiguous management signal is not assigned an interval and is not transmitted, while in other implementations, the contiguous management signal is assigned an interval and is transmitted. Figure 11 illustrates a diagram of contiguous and non-contiguous management signals being transmitted according to the steps of Figure 10.

[86] Using method 1000, an RD transmitting management signals might transmit less data than if the RD were to transmit contiguous management signals without transmitting non-contiguous management signals. Due to the reduction in spectrum efficiency that may occur when transmitting in long range mode, it might be preferable to use method 1000.

[87] Figure 11 illustrates a diagram 1100 of management signal transmissions according to one or more embodiments described herein. After a long range indicator signal 440 is transmitted, a contiguous management signal 1105 may be transmitted that comprises portions 1110-14. The portions 1110-14 may be ranked. For example portion 1110 may have a first rank, portion 1111 may have a second rank, portion 1112 may have a third rank, portion 1113 may have a fourth rank, and portion 1114 may have a fifth rank. Although the contiguous management signal 1105 is illustrated as being transmitted in order from portions 1110-14, the portions 1110-14 may be transmitted in any order or combination.

[88] After the contiguous management signal 1105, portions, or fields, of the contiguous management signal 1105 may be transmitted, e.g., non-contiguous management signals may be transmitted. At least some of portions of the non-contiguous management signals are not contiguous in time. At 1120, 1135, 1155, and 1170 a portion corresponding to the first rank may be transmitted. At 1125 and 1145 a portion corresponding to the second rank may be transmitted. At 1130 and 1165 a portion corresponding to the third rank may be transmitted. At 1150 a portion corresponding to the fourth rank may be transmitted. At 1160 a portion corresponding to the fifth rank may be transmitted. A second long range indicator 441 may or may not be transmitted prior to a second contiguous management signal 1140.

[89] An amount of time that elapses between the transmission of the first contiguous management signal 1105 and the second contiguous management signal 1140 may be referred to as a contiguous management signal interval. The contiguous management signal interval may be determined, or set, at step 1050 of figure 10.

[90] An amount of time that elapses between 1120 and 1135, 1135 and 1155, and 1155 and 1170 may comprise an interval determined for the first rank. An amount of time that elapses between 1125 and 1145 may comprise an interval determined for the second rank. An amount of time that elapses between 1130 and 1165 may comprise an interval determined for the third rank. The intervals between the portions of the management signal may be determined at step 1040 of figure 10.

[91] Figure 12 illustrates a table 1200 of management signal rankings according to one or more embodiments described herein. In the table 1200, portions of a contiguous management signal are ranked based on type of message field. Each rank comprises an interval time for portions of the management signal corresponding to that ranking. It should be understood that the information in table 1200 is exemplary, and that any number of rankings may be used, the illustrated message fields may be ranked differently, and the illustrated intervals may be changed. Figure 12 may be used at steps 1030 and 1040 of method 1000 to rank portions of the management signal and to assign intervals to each ranking.

[92] Figure 13 illustrates a block diagram of an example communication device according to one or more embodiments described herein. The example communication device, in particular, a computing device 1312, may be used in a communication network such as the one illustrated in figure 1, to implement any or all of SDs or RDs described and illustrated herein. Computing device 1312 may include a controller 1325 connected to a user interface control 1330, display 1336 and other elements as illustrated. Controller 1325 may include circuitry, such as one or more processors 1328 and one or more memory 1334 storing software 1340, for example, client software, user interface software, server software, etc.

[93] Device 1312 may also include a battery 1350 or other power supply device, speaker 1353, and one or more antennae 1354. Device 1312 may include user interface circuitry, such as user interface control 1330. User interface control 1330 may include controllers or adapters, and other circuitry, configured to receive input from or provide output to a keypad, touch screen, voice interface, for example, via microphone 1356, function keys, joystick, data glove, mouse and the like. The user interface circuitry and user interface software may be configured to facilitate user control of at least some functions of device 1312 though use of a display 1336. Display 1336 may be configured to display at least a portion of a user interface of device 1312. Additionally, the display may be configured to facilitate user control of at least some functions of the device (for example, display 1336 could be a touch screen).

[94] Software 1340 may be stored within memory 1334 to provide instructions to processor 1328 such that when the instructions are executed, processor 1328, device 1312 or other components of device 1312 are caused to perform various functions or methods such as methods 600, 900, 960, or 1000 or other steps described herein. The software may comprise machine executable instructions and data used by processor 1328 and other components of computing device 1312 may be stored in a storage facility such as memory 1334 or in hardware logic in an integrated circuit, ASIC, etc. Software may include both applications and operating system software, and may include code segments, instructions, applets, pre-compiled code, compiled code, computer programs, program modules, engines, program logic, and combinations thereof.

[95] In various embodiments, the SDs may include software that is configured to coordinate the transmission and reception of information to and from other devices through the RDs, other SDs, or the network. In one arrangement, client (e.g., SD) software may include specific protocols for requesting and receiving content through the wireless network. Client software may include instructions that cause one or more components, for example, a processor, wireless interface, or a display of the SDs, to perform various functions and methods including those described herein. The RDs may include similar software as the SDs.

[96] Memory 1334 may include any of various types of tangible machine-readable storage medium, including one or more of the following types of storage devices: read only memory (ROM) modules, random access memory (RAM) modules, magnetic tape, magnetic discs (for example, a fixed hard disk drive or a removable floppy disk), optical disk (for example, a CD-ROM disc, a CD-RW disc, a DVD disc), flash memory, and EEPROM memory. As used herein (including the claims), a tangible or non-transitory machine-readable storage medium is a physical structure that may be touched by a human. A signal would not by itself constitute a tangible or non- transitory machine-readable storage medium, although other embodiments may include signals or ephemeral versions of instructions executable by one or more processors to carry out one or more of the operations described herein.

[97] As used herein, processor 1328 (and any other processor or computer described herein) should be understood to encompass any of various types of well-known computing structures including but not limited to one or more microprocessors, special-purpose computer chips, field-programmable gate arrays (FPGAs), controllers, application- specific integrated circuits (ASICs), combinations of hardware/firmware/software, or other special or general-purpose processing circuitry.

[98] As used in this application, the term 'circuitry' may refer to all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone, wearable device, or server, to perform various functions) and (c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

[99] These examples of 'circuitry' apply to all uses of this term in this application, including in any claims. As an example, as used in this application, the term 'circuitry' would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term 'circuitry' would also cover, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or other network device

[100] Device 1312 or its various components may be mobile and be configured to receive, decode and process various types of transmissions including transmissions in a Wi-Fi networks according the IEEE 802.11 WLAN standards, (e.g., 802.11η, 802.1 lac, etc.) or wireless metro area network (WMAN) standards (e.g., 802.16), through a specific one or more WLAN transceivers 1343 and WMAN transceivers 1341. Additionally or alternatively, device 1312 may be configured to receive, decode, and process transmissions through various other transceivers, such as FM/AM radio transceiver 1342, and telecommunications transceiver 1344.

[101] Although the above description of figure 13 generally relates to a mobile device, other devices or systems may include the same or similar components and perform the same or similar functions and methods. For example, a computer 115 communicating over a wired network connection, or a wearable device 140, may include the components or a subset of the components described above, and may be configured to perform the same or similar functions as device 1312 and its components.

[102] Although specific examples of carrying out the invention have been described, those skilled in the art will appreciate that there are numerous variations and permutations of the above-described systems and methods that are contained within the spirit and scope of the invention as set forth in the appended claims.

Claims

We Claim:

1. A method, comprising:

receiving, by a computing device, a first management signal indicating a time for a transmission of a second management signal corresponding to a first communication mode; determining whether or not the computing device is able to decode the second management signal;

if the computing device was able to decode the second management signal, preventing the computing device from transmitting a signal on a busy tone slot; and

if the computing device was not able to decode the second management signal, transmitting the signal on the busy tone slot to indicate a request to communicate using a second communication mode.

2. The method of claim 1, wherein a number of subchannels of the first communication mode is greater than a number of subchannels of the second communication mode.

3. The method of claim 1, wherein the second communication mode is configured to communicate over a longer distance than the first communication mode.

4. The method of claim 1, wherein the first management signal indicating the time for the transmission of the second management signal further indicates a second time for the busy tone slot.

5. The method of claim 4, wherein the second time for the busy tone slot is subsequent to the time for the transmission of the second management signal.

6. The method of claim 1, further comprising receiving, after transmitting the signal on the busy tone slot, a third management signal corresponding to the second communication mode.

7. The method of claim 6, wherein the third management signal comprises a plurality of contiguous management signals.

8. The method of claim 6, further comprising, after receiving the third management signal, receiving a plurality of other management signals, wherein the management signals of the plurality of other management signals are smaller than the third management signal and are not contiguous in time.

9. The method of claim 1, further comprising:

decoding a third management signal corresponding to the first communication mode; and

in response to decoding the third management signal, transmitting a second signal, wherein the second signal indicates that the computing device will communicate in the first communication mode.

10. The method of claim 1, further comprising:

in response to determining that computing device was not able to decode the second management signal, initializing a counter;

incrementing the counter in response to receiving a third management signal;

determining that the counter is greater than a predetermined threshold; and

in response to determining that the counter is greater than the predetermined threshold, waking up at a scheduled time to receive a fourth management signal corresponding to the first communication mode.

11. The method of claim 10, further comprising, in response to determining that the computing device was not able to decode the fourth management signal, resetting the counter.

12. The method of claim 10, further comprising, in response to determining that the computing device was able to decode the fourth management signal, transmitting a second signal, wherein the second signal indicates that the computing device will communicate in the first communication mode.

13. The method of claim 1, wherein the first management signal comprises a long range indicator and the second management signal comprises a short range management signal.

14. An apparatus comprising: at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:

receive a first management signal indicating a time for a transmission of a second management signal corresponding to a first communication mode;

determine whether or not the apparatus is able to decode the second management signal;

if the apparatus was able to decode the second management signal, prevent the apparatus from transmitting a signal on a busy tone slot; and

if the apparatus was not able to decode the second management signal, transmit the signal on the busy tone slot to indicate a request to communicate using a second communication mode.

15. The apparatus of claim 14, wherein a number of subchannels of the first communication mode is greater than a number of subchannels of the second communication mode.

16. The apparatus of claim 14, wherein the second communication mode is configured to communicate over a longer distance than the first communication mode.

17. The apparatus of claim 14, wherein the first management signal indicating the time for the transmission of the second management signal further indicates a second time for the busy tone slot.

18. The apparatus of claim 17, wherein the second time for the busy tone slot is subsequent to the time for the transmission of the second management signal.

19. The apparatus of claim 14, wherein the computer program code is further configured to cause the apparatus to receive, after transmitting the signal on the busy tone slot, a third management signal corresponding to the second communication mode.

20. The apparatus of claim 19, wherein the third management signal comprises a plurality of contiguous management signals.

21. The apparatus of claim 20, wherein the computer program code is further configured to cause the apparatus to, after receiving the third management signal, receive a plurality of other management signals, wherein the management signals of the plurality of other management signals are smaller than the third management signal and are not contiguous in time.

22. The apparatus of claim 14, wherein the computer program code is further configured to cause the apparatus to:

decode a third management signal corresponding to the first communication mode; and

in response to decoding the third management signal, transmit a second signal, wherein the second signal indicates that the apparatus will communicate in the first communication mode.

23. The apparatus of claim 14, wherein the computer program code is further configured to cause the apparatus to:

in response to determining that the apparatus was not able to decode the second management signal, initialize a counter;

increment the counter in response to receiving a third management signal;

determine that the counter is greater than a predetermined threshold; and

in response to determining that the counter is greater than the predetermined threshold, wake up at a scheduled time to receive a fourth management signal corresponding to the first communication mode.

24. The apparatus of claim 23, wherein the computer program code is further configured to cause the apparatus to, in response to determining that the apparatus was not able to decode the fourth management signal, reset the counter.

25. The apparatus of claim 23, wherein the computer program code is further configured to cause the apparatus to, in response to determining that the apparatus was able to decode the fourth management signal, transmit a second signal, wherein the second signal indicates that the apparatus will communicate in the first communication mode.

26. The apparatus of claim 14, wherein the first management signal comprises a long range indicator and the second management signal comprises a short range management signal.

27. A method, comprising:

transmitting, by a computing device, an indication of a channel reservation for a transmission opportunity comprising a busy tone slot;

transmitting a first management signal corresponding to a first communication mode; and

in response to determining that a busy tone signal was received during the busy tone slot, transmitting a second management signal for a second communication mode.

28. The method of claim 27, wherein a number of subchannels of the first communication mode is greater than a number of subchannels of the second communication mode.

29. The method of claim 27, wherein determining that the busy tone signal was received during the busy tone slot comprises measuring an energy level during the busy tone slot.

30. The method of claim 27, further comprising:

communicating with a first at least one device via the first communication mode; and communicating with a second at least one device via the second communication mode.

31. The method of claim 27, wherein the second communication mode is configured to communicate over a longer distance than the first communication mode.

32. An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to:

transmit an indication of a channel reservation for a transmission opportunity comprising a busy tone slot;

transmit a first management signal corresponding to a first communication mode; and

in response to determining that a busy tone signal was received during the busy tone slot, transmit a second management signal for a second communication mode.

33. The apparatus of claim 32, wherein a number of subchannels of the first communication mode is greater than a number of subchannels of the second communication mode.

34. The apparatus of claim 32, wherein the computer program code that is configured to cause the apparatus to determine that the busy tone signal was received during the busy tone slot comprises code that is configured to cause the apparatus to measure an energy level during the busy tone slot.

35. The apparatus of claim 32, wherein the computer program code is further configured to cause the apparatus to:

communicate with a first at least one device via the first communication mode; and communicate with a second at least one device via the second communication mode.

36. The apparatus of claim 32, wherein the second communication mode is configured to communicate over a longer distance than the first communication mode.