Wireless private branch exchange (WPBX) and communicating between mobile units and base stations

• US 20020147016A1
• Filed: 02/20/2002
• Published: 10/10/2002
• Est. Priority Date: 04/07/2000
• Status: Active Grant

• Current Assignee: Commil USA LLC (Commil)
• Original Assignee: Commil USA LLC (Commil)
• Inventors: Barak, Haim, Arazi, Nitzan, Soffer, Yaron
• Granted Patent: US 7,107,057 B2
• Time in Patent Office: Days
• US Class Current: 455/443
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: H04M 1/725 Cordless telephones user interfaces specially adapted therefor H04M1/724
• CPC Class Codes: H04M 1/733 with a plurality of base stations connected to a plurality of lines for selection in cordless PBX H04W84/16
• CPC Class Codes: H04M 2250/02 including a Bluetooth interface
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 76/00 Connection management
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/105 PBS [Private Base Station] network H04W84/12 - H04W84/16 take precedence
• CPC Class Codes: H04W 84/16 WPBX [Wireless Private Branch Exchange]
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

Methods to create a cellular-like communication system, such as a Wireless Private Branch Exchange (WPBX), which includes mobile devices such as standard cordless phones (handsets), particularly, mobile devices utilizing the Bluetooth short-range wireless communication protocol. The methods provide seamless and reliable handoff of sessions between Base Stations while the mobile device is moving between picocells, by implementing a high-level of synchronization between the Base Stations and the Switch. Base Stations of picocells having small coverage areas communicate with the handsets. The communication protocol is divided into a low-level protocol performed by the Base Stations and a high-level protocol performed by the Switch connected to all the Base Stations. The methods support mobile computing or telephony devices and communication protocols, which are not specified to handle handoffs of sessions while moving between Base Stations coverage areas in a data, voice or telephony wireless network.

Claims

1. In a wireless communication system comprising a Base Station connected with a mobile unit, a method of detecting the presence of a specific mobile unit in a coverage area of at least one neighboring Base Station, comprising:

the Base Station connected with the mobile unit provides, to the at least one neighboring Base Station, information about the connection with the mobile unit, including rough TOD and a device address for the mobile unit;

at the at least one neighboring Base Station, receiving information and generating a list of frequencies in which the mobile unit is likely to transmit; and

at the at least one neighboring Base Station, checking for a signal transmitted by the mobile unit.

2. Method, according to claim 1, further comprising:

at the neighboring Base Station, monitoring frequencies that are not blocked by interferences

3. Method, according to claim 2, further comprising:

for each frequency that is monitored, maintaining a histogram of a number of hops that have been detected in a certain duration of time, and their average signal-to-noise ratios.

4. Method, according to claim 3, further comprising:

determining a measure of spectral cleanness of a frequency being monitored as a function of signal-to-noise ratios (SNRs) of the hops.

5. Method, according to claim 4, further comprising:

monitoring a group (M) of frequencies that have a best cleanness measure most of the time.

6. Method, according to claim 5, further comprising:

periodically monitoring a frequency which is not in the group of frequencies having the best cleanness measure.

7. Method, according to claim 1, wherein the mobile unit is a device selected from the group consisting of:

telephone handset, standard cordless telephone handset, cellular telephone handset, personal data device, personal digital assistant (PDA), computer, laptop computer, e-mail server, a device utilizing point-to-point protocol (PPP) to the Internet via a central remote access server, a headset, a personal server, a wearable computer, a wireless camera, and a mobile music player.

8. Method, according to claim 1, further comprising:

providing communication links between the Base Stations, wherein the communication links between the Base Stations are selected from the group consisting of RF links and land lines; and

transferring connection status information and rough synchronization information between the Base Stations over the communications links.

9. Method, according to claim 1, wherein:

the Base Stations and the Switch are connected via a wired or wireless local area network (LAN).

10. Method, according to claim 1, wherein:

the wireless communication system comprises a wireless private branch exchange (WPBX) handling calls from mobile units comprising handsets.