Source: https://patents.google.com/patent/US7251489
Timestamp: 2018-07-21 19:45:03
Document Index: 60333587

Matched Legal Cases: ['Application No. 60', 'application No. 60', 'application No. 60', 'application No. 60', 'application No. 60', 'application No. 60', 'application No. 60']

US7251489B2 - Wireless base station neighbor discovery in a communication system, such as a system employing a short-range frequency hopping scheme - Google Patents
US7251489B2
US7251489B2 US10700788 US70078803A US7251489B2 US 7251489 B2 US7251489 B2 US 7251489B2 US 10700788 US10700788 US 10700788 US 70078803 A US70078803 A US 70078803A US 7251489 B2 US7251489 B2 US 7251489B2
US10700788
US20040106408A1 (en )
This application is a continuation of international application no. PCT/US02/13880 filed May 2, 2002, and claims the benefit of U.S. Provisional Patent Application No. 60/288,296, filed May 2, 2001, both of which are incorporated by reference.
Currently, the most well-known attempt to provide features that PCN offers in a mobile environment is referred to as 3G- (third generation) wireless. 3G-wireless, however, is constrained by factors that do not constrain PCN implementations. These include heavy investment for the acquisition of spectrum usage rights.
The above wireless technologies require knowledge of which BSUs in a network have coverage overlap with other, neighboring BSUs within the network. Such overlap is a prerequisite for BSU to BSU handoff occurring without links getting dropped. Each BSU is typically given the knowledge of BSUs to which they can hand off. One example of this is the GSM system, in which each BSU is under the control of a BSU controller. See, “Mobile Communications”, Jochen Schiller, pp. 84-112 (Addison-Wesley, 2000). In the GSM system, the BSU controllers and the devices that coordinate them (mobile services switching center) are what decide when and where to hand off. A network can have a potentially large number of BSUs, so it can require significant time and effort to inform each BSU about which other BSUs can receive handoffs from it.
FIG. 3 is a block diagram of a multiple subnet architecture where BSUs and mobile units are assigned addresses that fall within multiple IP subnets. In this embodiment the mobile units belong to a separate subnet dedicated to the MUs and their point of presence [330].
FIG. 5 is a block diagram illustrating an inter-subnet handoff of a mobile unit from a BSU in one subnet to a BSU in another subnet under the network of FIG. 3
Aspects of the invention are described in detail below with respect to the Bluetooth specification. Bluetooth refers to a specification designed to standardize wireless transmission between a wide variety of devices, such as personal computers (“PCs”), cordless telephones, headsets, printers, personal digital assistants (“PDAs”), etc. Bluetooth acts as a “virtual cable,” whereby a computer can automatically use a mobile telecommunications device (such as a cell phone) to send data wirelessly, such as exchange e-mail, transmit data to a fax machine, etc. Bluetooth operates in the unlicensed 2.4 GHz spectrum using frequency-hopping spread spectrum, where data packets are spread across the Bluetooth spectrum at a nominal rate of 1,600 hops per second to lessen interference and fading. According to the Bluetooth specification, Bluetooth devices operate their antennas at one of three different maximum antenna power levels, i.e., 1 mW, 2.5 mW and 100 mW. The nominal link range is 10 meters, and the gross data rate is 1 Mbps, although increases may be possible. Bluetooth can support both synchronous connection oriented (“SCO”) links for voice and asynchronous connectionless (“ACL”) links for packet data. Details on Bluetooth may be found at http://www.bluetooth.com, “Bluetooth Revealed,” Miller & Bisdikian, Prentice Hall PTR, 2001, and “Bluetooth Demystified,” Muller, McGraw-Hill, 2001, and in particular, “Specification of the Bluetooth System,” version 1.1: httf://www.bluetooth.com/developer/specification/specification.asp.
When the MU 104 moves, it may move within the range of another BSU (e.g. shown in FIG. 1 as the MU moving from location 1 near the first BSU. 102 to location 2 near the neighbor BSU 108, where the MU establishes a new link with the neighbor BSU 108). If the MU moves beyond the range of the first BSU 102, the link with the neighbor BSU 108 can be used to maintain uninterrupted communication with the network, provided that a new link is established before the link with the first BSU is lost. In other words, the MU 104 must establish a link 2 with the BSU 108 in a new domain 109.
The BSUs may each be directly connected to the PMN by using appropriate cabling, such as Category 5 cabling. Such cabling is necessary to provide not only a signal path therebetween, but may also supply power to the BSU. Alternatively, a link with the BSU controller may be accomplished via wireless techniques. Wiring may be required, however, to provide power to the BSUs.
Thus, once a network has been operating for some period of time and neighbor discovery has, occurred in the manner described, additional BSUs may come online that would need to become integrated into the network. Similarly, BSUs may go offline and their resources would become unavailable to the network for some period of time. To handle new BSUs that come online and to have offline BSUs' absences detected and their resources recognized as unavailable, each BSU's list of neighbors must be kept current.
At the intermediate power, the BSU B11 under block 706 additionally would discover BSUs B9, B5, B2, B3, B4, B8, B16, B20, B19, B18, and B13. These would be classified as “second tier” neighbors based on their presumed greater distance from the discovering BSU. This is illustrated in FIG. 9. They may not in fact all be at a greater distance—RF environment factors could, for example, be attenuating the wireless signal. For whatever physical reason, BSUs that are not detected under block 704 but are detected under block 706 are termed “second tier.” Additional neighbors, may be discovered under block 708. The hierarchy of tiers may of course be expanded to additional tiers (beyond 3).
In one embodiment, each BSU employs various layers of software under the Bluetooth protocol. Each BSU may thus further include radio environment monitoring (“REMon”) and radio environment management (“REMan”) software, which includes a REMan component that operates above the host controller interface (“HCI”), and a REMon component that operates below the HCI, together with baseband components of the Bluetooth protocol. The REMan component receives information regarding existing links and neighboring BSUs, and evaluates performance indicators of each link. The REMon component performs link quality measurements for REMan. BSU neighbor discovery under the routine 700 is performed with the REMan component, within the radio environment monitoring and management software, and above the HCI.
In a second alternative embodiment, each BSU sends periodic heartbeat messages directly to each. BSU that considers them a neighbor. The periodic heartbeat messages may be transmitted between neighboring BSUs either wirelessly or via wired connections. Unlike the prior alternative embodiment, this embodiment does not depend on the system controller 208. After performing blocks 702-712 (FIG. 7), each BSU sends a “you're my neighbor” message to each BSU in its neighbor list, and also starts maintaining a timer for each neighbor. It then starts expecting heartbeat messages from each of its neighbors on a regular basis. When a neighbor's heartbeat messages become absent long enough for the timer to have expired, then that BSU can be deemed down and may be removed by the BSU from its neighbor list. For example, referring to FIG. 8: when BSU B6 misses one or more messages from neighbor BSU B11, B6 can assume B11 is having trouble. BSU B6 can remove BSU B11 from B6's neighbor list and will no longer hand off to B11.
An initialization time field 1206 identifies the date and time that the neighbor was first detected. A rediscovery time field 1208 corresponds to the date and time that the neighbor was detected during the most recent periodic neighbor rediscovery. A neighbor's synchronization master field 1210 corresponds to a predetermined BD_ADDR to which the neighbor synchronizes its clock. Wireless BSU synchronization and use of a sync master address are described in further detail in U.S. patent application No. 60/288,294, entitled “Wireless System BSU to BSU Synchronization”. A record expiration field 1212 identifies when this record will expire and need refreshing, as noted above.
Incorporated by reference herein are all above references, patents, or applications and the following U.S. provisional applications, which are assigned to the assignee of this application: application No. 60/262,558, entitled Link Context Mobility, Such as for use in Wireless Networks, filed Jan. 18, 2001; application No. 60/288,294, entitled Wireless System Base Station to Base Station Synchronization; application No. 60/288,270, entitled Method for Load Balancing Wireless Networks; application No. 60/288,301, entitled Frequency-Hopping Spread Spectrum Wireless Systems Interface Migration by Transmit Suppression; and application No. 60/288,300, entitled Visual Base Station to Wireless Link Quality Indicator.
a second base station unit coupled to the network, wherein the first and second base station units are configured to communicate wirelessly with the mobile unit under a Bluetooth protocol and to automatically handoff the mobile unit from the first base station unit to the second base station unit;
wherein the first and second base station units are configured to:
use a low power class capability to inquire whether Bluetooth compatible devices are within a near communications range;
use a medium power class capability to inquire whether Bluetooth compatible devices are within an intermediate communications range;
use a high power class capability to inquire whether Bluetooth compatible devices are within a far communications range;
store at least one record that identifies any Bluetooth compatible devices are within the near, intermediate and far communications ranges;
identify which devices are base station units capable of accepting the mobile unit during a handoff, wherein identification of base station units results from a wireless inquiry signal from the identifying base station and a wireless response signal back from the identified base stations; and
update the at least one record to reflect changes in base station units capable of accepting the mobile unit during a handoff.
2. The system of claim 1, further comprising a system controller coupled to the first and second base station units and to the network, wherein the system controller is configured to mediate communications between the first and second base stations and the network,
wherein the low, medium and high power classes include 0 dB, 4 dB and 20 dB power classes, respectively,
wherein identifying which devices are base station units capable of accepting the mobile unit during a handoff includes employing a Bluetooth service discovery protocol to identify services associated with identified devices; and
wherein updating the at least one record includes again using the low, medium and high power class capabilities to inquire whether Bluetooth compatible devices are within the near, intermediate and far communications ranges, and updating the at least one record when a rediscovery period has expired.
3. The system of claim 1 wherein updating the at least one record includes:
sending periodic signals to neighboring base station units, wherein the periodic signals include information identifying the base station unit that sends the periodic signals;
receiving periodic signals from at least one neighboring base station unit;
determining an identity of the one neighboring base station unit based on the received periodic signals; and
updating the at least one record if a periodic signal is not received from a previously neighboring base station.
4. A method of creating a list of neighboring base station units in a wireless communications network, wherein at least one mobile unit communicates with at least a portion of the network, the method of creating the list of neighboring base station units comprising:
at a stationary base station unit in the communications network, wirelessly sending at least one inquiry signal to neighboring wireless devices, using a low power class capability and a high power class capability to inquire whether wireless devices are within a near communications range and a far communications range, respectively;
at the stationary base station unit in the communications network, identifying the one neighboring base station unit based in part on the received response signal, wherein identifying the at least one neighboring base station unit is done without involvement of me mobile unit and without Involvement of a system controller for the communications network; and
at the stationary base station unit in me communications network, providing a stored neighbor list that identifies the one neighboring base station unit in the communications network;
wherein the base station unit and the neighboring base station unit are both Bluetooth enabled base station units;
wherein sending at least one inquiry signal includes wirelessly sending a Bluetooth inquiry signal with respect to at least two different power classes; wherein identifying the one neighboring base station unit includes employing a Bluetooth service discovery protocol to identify two or more neighboring base station units; and
5. The method of claim 4 wherein sending at least one inquiry signal and receiving a response signal includes wirelessly exchanging signals under a Bluetooth protocol.
6. The method of claim 4 wherein identifying the one neighboring base station unit includes employing a Bluetooth service discovery protocol.
7. The method of claim 4 wherein providing a stored neighbor list includes locally storing a list categorizing identified neighboring base station units into at least two different categories.
8. The method of claim 4, further comprising automatically updating the stored neighbor list to reflect changes in neighboring base station units, and wherein sending at least one inquiry signal and receiving a response signal is performed wirelessly between the base station unit and the neighboring base station unit.
9. The method of claim 4, further comprising updating the stored neighbor list to reflect changes in neighboring base station units by again sending at least one inquiry signal and receiving a response signal, and updating the stored neighbor list, when a predetermined time period has expired.
10. The method of 4, further comprising updating the stored neighbor list to reflect changes in the one neighboring base station unit, wherein updating the stored neighbor list comprises:
11. The method of claim 4, further comprising receiving periodic signals from the one neighboring base station unit, and updating the stored neighbor list if a periodic signal is not received from the one neighboring base station.
12. The method of claim 4, further comprising determining whether a certain time period associated with at least a portion of the stored neighbor list has expired, and if so, then again sending at least one inquiry signal, receiving a response signal, and updating the stored neighbor list.
13. The method of claim 4, further comprising providing periodic signals to a system controller, and updating the stored neighbor list based on a command signal received from the system controller.
14. The method of claim 4, further comprising determining whether a certain time period has expired, and if so, then again sending at least one inquiry signal, receiving a response signal, and updating the stored neighbor list.
15. The method of claim 4, further comprising receiving a command signal from a system controller coupled to the base station unit, and in response thereto, again sending at least one inquiry signal, receiving a response signal, and updating the stored neighbor list.
16. The method of claim 4 wherein the stationary base station unit is stationary relative to a moving vehicle.
17. The method of claim 4 wherein providing a stored neighbor list includes locally storing a list categorizing the identified neighboring base station units into at least one category.
18. A computer-readable storage medium encoded with a computer program whose contents cause a fixed short-range wireless communications switch to perform a peer-to-peer method to provide a neighbor list for neighboring and fixed short-range wireless communications switches in a communications network, wherein at least one mobile unit communicates with at least a portion of the communications network, the method comprising:
at the fixed short-range wireless switch in the communications network, sending at least one signal to neighboring wireless devices, wherein sending the signal is done without assistance of the mobile unit and without the assistance of a system controller for the communications network, using a low power class capability and a high power class capability to inquire whether wireless devices are within a near communications range and a far communications range, respectively;
at the fixed short-range wireless switch in the communications network, receiving a response signal from at least one fixed neighboring short-range wireless switch;
at the fixed short-range wireless switch in the communications network, identifying the one neighboring short-range wireless switch based on the received response signal, wherein identifying the one fixed neighboring short-range wireless switch results from direct and wireless communication between the fixed short-range wireless switch and the one fixed neighboring short-range wireless switch without assistance of the mobile unit or system controller; and
providing a neighbor list that identifies the one neighboring short-range wireless switch.
19. The computer-readable storage medium of claim 18 wherein the computer-readable medium is a computer-readable disk.
20. The computer-readable storage medium of claim 18 wherein the computer-readable medium is a memory of a computer system.
21. In a short-range wireless communications network, wherein at least one mobile unit communicates with at least a portion of the network, an apparatus comprising:
means for wirelessly sending at least one signal to neighboring wireless devices using a low power class capability and a high power class capability to inquire whether wireless devices are within a near communications range and a far communications range, respectively, wherein sending the signal is done without assistance of the mobile unit and without the assistance of a system controller for the communications network;
22. The apparatus of claim 21 wherein the means for sending at least one inquiry signal and the means for receiving a response signal include wirelessly exchanging signals under a Bluetooth protocol.
23. The apparatus of claim 21 wherein the means for providing further comprises means for locally storing a list categorizing identified neighboring short-range network nodes into at least two different categories.
24. The apparatus of claim 21 wherein the fixed means for providing short-range wireless communications provides wireless communications under a standard protocol for a range up to about 500 meters.
US10700788 2001-05-02 2003-11-03 Wireless base station neighbor discovery in a communication system, such as a system employing a short-range frequency hopping scheme Active 2023-08-13 US7251489B2 (en)
PCT/US2002/013880 Continuation WO2002103988A1 (en) 2001-05-02 2002-05-02 Wireless base station neighbor discovery in a communication system employing a short-range frequency hopping scheme
US20040106408A1 true US20040106408A1 (en) 2004-06-03
US7251489B2 true US7251489B2 (en) 2007-07-31
US20070198671A1 (en) * 2006-02-09 2007-08-23 Tetsuro Motoyama System, computer program product and method for using a wireless device to control a wireless network device
JP5392085B2 (en) * 2007-10-01 2014-01-22 日本電気株式会社 Wireless communication system, radio communication method, a base station, mobile station, the control method of the base station, control method and control program for the mobile station
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US7546126B2 (en) 2009-06-09 grant
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KUIKEN, MATTHEW;REEL/FRAME:014670/0274
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BEASLEY, JAMES;DOMBROWSKI, DENNIS;MERGENTHAL, WADE;AND OTHERS;REEL/FRAME:014667/0512