Mobile radio communication system

• US 6,937,858 B2
• Filed: 02/13/2002
• Issued: 08/30/2005
• Est. Priority Date: 08/26/1998
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Itou, Shuuji, Tomisawa, Toshiaki, Take, Keijiro
• Primary Examiner(s): Ferguson, Keith
• Application Number:
  US10/073,320
• Publication Number:
  US 20020072366A1
• Time in Patent Office: 1,294 Days
• Field of Search: 455/550.1, 455/456.1, 455/456.2, 455/456.6, 455/404.1, 455/404.2, 455/422.1, 455/403, 455/432.1, 455/11.1, 455/15, 455/16, 455/561, 455/562.1, 455436-444, 455/455, 455/434, 455/553.1, 455/575.1, 455/575.7, 455/90.3, 455/500, 455/517, 455/3.05, 455/456, 455/562, 455/435, 455/445, 342/386, 342/408, 342/417, 342/432, 342/434, 342/444, 342/450, 342/457, 342/463, 342/419
• US Class Current: 455/432.1
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 36/16 Performing reselection for specific purposes

Abstract

A mobile radio communication system which does not need an omnidirectional channel for both a base station and a mobile station to track each other and uses only a narrow beam channel and can reduce a tracking time than before for an adjacent base station and a mobile station to search each other while a visiting area base station and the mobile station are communicating in the overlapped area. The base station and the mobile station comprise a unit for transmitting and receiving in forward or reverse channel, in different frequency, in different tracking channel using a narrow beam. Both the mobile station and the visiting area base station search the location each other, and after searched, they assign the frequency and the beam used in the tracking channel. At the same time, by comprising a searching slot in an information channel to search an adjacent base station while communicating with the visiting area base station, a tracking of other adjacent base station can be performed.

Claims

1. A mobile station comprising:

a controller for varying the direction of reception for receiving a narrow forward tracking beam in a tracking channel at a certain frequency, the narrow forward tracking beam being transmitted from at least one base station covering an area into which the mobile station enters, for transmitting a narrow reverse tracking beam in the tracking channel and for varying the direction of the reverse tracking beam,

wherein upon completion of a tracking process in which the mobile station and the at least one base station track each other'"'"'s position relative to each other using the narrow tracking beams, the mobile station and the at least one base station switch to an information channel using the same frequency and direction as the tracking channel.

2. The mobile station according to claim 1, wherein the mobile station is adapted to track an adjacent base station covering an area adjacent to the area covered by the at least one base station by receiving the narrow forward tracking beam of the adjacent base station during communication with the at least one base station.

3. The mobile station according to claim 2, wherein a searching slot is provided in the information channel used by the at least one base station and the mobile station, and wherein the mobile station searches for the adjacent base station using the searching slot during communication with the at least one base station.