Multisite radio system with false mobile radio signalling detection

• US 5,875,211 A
• Filed: 10/26/1995
• Issued: 02/23/1999
• Est. Priority Date: 10/26/1995
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson), The Research Triangle Park (The PNC Financial Services Group, Inc.)
• Inventors: Cooper, Gerald M.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US08/548,828
• Time in Patent Office: 1,216 Days
• Field of Search: 375/213, 371/37.7, 371/2.1, 371/20.2, 380/25, 380/30, 380/43, 380/44, 379/58, 379/59, 455/7, 455/33.1
• US Class Current: 375/213
• CPC Class Codes: H04W 84/08 Trunked mobile radio systems

Abstract

In a digitally trunked radio repeating system that may include several radio site repeating transceivers, a site area identification coding system to ensure that transmissions intended for one site or as one mode are not decoded by another site or as another transmission mode. In particular, a site or transmission mode identification byte is used in the transmission error coding (CRC) scheme applied by both a mobile transceiver and the radio site repeater. Since the identification byte is used in the transmitter to calculate the CRC error correction data, the same identification byte must be used in the receiver to decode the CRC value. The intended radio site or transmission mode wilt apply the proper identification byte to decode a transmission. The wrong radio site or mode will not correctly decode the CRC value in a transmission because the wrong identification byte will be applied to the transmission. Accordingly, a transmission received by the wrong radio site or at a transceiver operating in a mode different that the transmission will not properly decode the transmission due to a CRC error caused by applying the wrong identification byte.

Claims

1. A method for communicating digital signals between a radio frequency (RF) mobile radio unit and an RF base station site having a controller comprising:

(a) packaging digital information to be transmitted from the mobile radio units in a series of bytes;

(b) assembling a predetermined number of the series of bytes from step (a) for transmission;

(c) calculating an error detection value dependent upon the bytes assembled in step (b) and at least one non-transmitted identification byte having a first predetermined bit setting, where said bit setting is relatively unique, and where the at least one non-transmitted identification byte is defined by data previously received by the mobile radio unit from an assigned base station site;

(d) transmitting the bytes assembled in step (b) with the error detection value calculated in step (c) from the mobile radio unit and reception of the transmission by an RF base station site;

(e) calculating in the base station site controller an error detection value from the bytes received in step (d) and from at least one identification byte stored in the site controller, where the at least one identification byte stored in the site controller for the assigned base station site corresponds to the at least one non-transmitted identification byte defined by the data previously received by the mobile radio;

(f) comparing in the base station site controller the error detection value calculated in step (e) to the error detection value received in step (d);

(g) decoding the bytes received in step (d) if the comparison in step (f) matches the two error detection values;

(h) discarding the bytes received in step (d) if the comparison in step (f) does not match the two error detection values, and

(j) prior to step (a), the mobile radio unit receives information identifying the non-transmitted byte from a base station site in conjunction with assigning the mobile radio to the site.

2. A method for communicating digital signals as in claim 1 wherein in step (c) the calculation of an error detection valve is a cyclic redundancy check code (CRC).

3. A method for communicating digital signals as in claim 1 wherein in step (c) the non-transmitted identification byte having a first predetermined bit setting is selected from a group of bit setting each of which bit settings is all zero bits except for a single 1 bit.

4. A method for communicating digital signals between a radio frequency (RF) radio unit and an RF repeater site having a controller comprising:

(a) packaging digital information to be transmitted from the radio units in a series of bytes;

(b) assembling a predetermined number of the series of bytes from step (a) for transmission;

(c) calculating an error detection value dependent upon the bytes assembled in step (b) and a non-transmitted identification byte having a first predetermined bit setting, where said bit setting is relatively unique;

(d) transmitting the bytes assembled in step (b) with the error detection value calculated in step (c) from the radio unit and reception of the transmission by RF repeater site;

(e) calculating in the repeater site controller an error detection value from the bytes received in step (d) and from an identification byte stored in the site controller;

(f) comparing in the repeater site controller the error detection value calculated in step (e) to the error detection value received in step (d);

(g) decoding the bytes received in step (d) if the comparison in step (f) matches the two error detection values;

(h) discarding the bytes received in step (d) if the comparison in step (f) does not match the two error detection values, and wherein before step (a) the following steps are performed;

(i) the radio unit receives a site identification message from the repeater site in conjunction with the unit logging into the site, which message defines the non-transmitted identification bit setting applied in step (c),

(j) the radio unit temporarily stores the non-transmitted bit setting as the non-transmitted identification bit setting applied in step (c).

5. A method for communicating digital signals between a radio frequency (RF) radio unit and an RF repeater site having a controller comprising:

(a) packaging digital information to be transmitted from the radio units in a series of bytes;

(b) assembling a predetermined number of the series of bytes from step (a) for transmission;

(c) calculating an error detection value dependent upon the bytes assembled in step (b) and a non-transmitted identification byte having a first predetermined bit setting, where said bit setting is relatively unique;

(d) transmitting the bytes assembled in step (b) with the error detection value calculated in step (c) from the radio unit and reception of the transmission by RF repeater site;

(e) calculating in the repeater site controller an error detection value from the bytes received in step (d) and from an identification byte stored in the site controller;

(f) comparing in the repeater site controller the error detection value calculated in step (e) to the error detection value received in step (d);

(g) decoding the bytes received in step (d) if the comparison in step (f) matches the two error detection values;

(h) discarding the bytes received in step (d) if the comparison in step (f) does not match the two error detection values, and

wherein before step (a) the following steps are performed;

(k) the radio unit latches onto a working channel of the RF repeater site as the unit enters a broadcast coverage area of the RF repeater site;

(l) the radio unit receives on the working channel a site identification message from the repeater site, which message defines the non-transmitted identification bit setting applied in step (c), and

(m) the radio unit temporarily stores the non-transmitted identification bit setting as the non-transmitted identification bit setting applied in step (c).

6. A method for communicating digital signals between a radio frequency (RF) radio unit and a multisite radio system having at least a first and second RF repeater site, where each site has a controller and the sites are interconnected by a switch, the method comprises the following steps:

(a) the radio unit when logged into the first RF repeater site controller stores in a temporary memory of the radio unit a non-transmitted identification byte having a first predetermined bit setting where said bit setting is relatively unique to the first RF repeater site;

(b) the radio unit packages digital information to be transmitted from the radio units in a series of bytes to the first RF repeater site;

(c) the radio unit assembles a predetermined number of the series of bytes from step (b) for transmission to the first RF repeater site;

(d) calculating an error detection value dependent upon the bytes assembled in step (c) and the non-transmitted identification byte;

(e) transmitting the bytes assembled in step (c) with the error detection value calculated in step (d) from the radio unit and reception of the transmission by first RF repeater site;

(f) calculating in the site controller an error detection value from the bytes received in step (e) and from an identification byte stored in the first RF repeater site controller;

(g) comparing in the first RF repeater site controller the error detection value calculated in step (f) to the error detection value received in step (e);

(h) decoding the bytes received in step (e) if the comparison in step (g) matches the two error detection values;

(i) discarding the bytes received in step (e) if the comparison in step (f) does not match the two error detection values,

(j) the radio unit when logged into the first RF repeater site moves away from the first RF repeater site, and looses adequate reception of a working channel broadcast from the first RF repeater site and begins scanning for a working channel;

(k) the radio unit latches onto a working channel of the second RF repeater site as the unit enters a broadcast coverage area of the second RF repeater site; and

(l) the radio unit receives on the working channel a site identification message from the second RF repeater site, which message defines a second non-transmitted identification bit setting relatively unique to the second RF repeater site.

7. A method for communicating digital signals between a radio frequency (RF) radio unit and an RF repeater site having a controller comprising:

(a) packaging digital data information to be transmitted from the radio units in a series of data bytes to be transmitted from the radio unit to the RF repeater site;

(b) setting a first transceiver in the RF repeater site to a data mode and a second transceiver in the RF repeater site to a voice mode;

(c) assembling into a signal data package a predetermined number of the data bytes;

(d) calculating a first error detection value dependent upon the data bytes assembled in step (c), and a first non-transmitted data identification byte;

(e) transmitting from the radio unit the data bytes assembled in step (c) with the error detection value calculated in step (d);

(f) calculating in the repeater site controller an error detection value using the data bytes received by the first transceiver and a data identification byte stored in the site controller;

(g) comparing in the repeater site controller the error detection value calculated in step (f) to the error detection value from step (e), and

(h) decoding the data bytes received by the transceiver in data mode, if the comparison in step (g) matches the two error detection values;

(i) calculating in the repeater site controller an error detection value using the data bytes received by the second transceiver set to voice mode and a voice identification byte store in the site controller;

(j) comparing in the repeater site controller the error detection value calculated in step (i) to the error detection value received by the second transceiver, and

(k) discarding the bytes received by the second transceiver if the comparison in step (j) does not match the two error detection values.

8. A method for communicating digital signals as in claim 7 wherein the calculations of an error detection valve is a cyclic redundancy check code (CRC).