EP0577322A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus and method for call handover in a cellular radio system
Assignee: Nokia Oyj
•
Filing: 1993-06-23
•
Granted: —
•
Expires: 2013-06-23
Abstract
Abstract In preparation of a handover from base station BTS1 to base station BTS2 parallel physical links (R1,R2) are formed between the mobile station MS and the two base stations (BTS1,BTS2), whereby these base stations (BTS1,BTS2) transmit the same signal to the mobile station MS in different time slots and possibly on different frequencies.
Inventors
- 👤 Esa Malkamaki
- 👤 Harri Jokinen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 10:58
CPC Classifications
H; H04; H04W; H04W36/00; H04W36/16; H04W36/18
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
19 words
Apparatus for performing handover in a cellular radio system, wherein two different communication channels are utilized during the handover.
Claim 2
Dependent Claim
93 words
Apparatus according to claim 1, further comprising a first base station (BTS1) and a second base station (BTS2) and at least one mobile station (MS) and wherein there is provided means for communicating between the second base station (BTS2) and the at least one mobile station (MS) via a second base station (BTS2) communication channel which is different to a communication channel utilized by the first base station (BTS1) for communicating with the at least one mobile station (MS) during handover between the first base station (BTS1) and the second base station (BTS2).
Claim 3
Dependent Claim
71 words
Apparatus according to claim 2, further comprising: a) monitoring means for monitoring signals transmitted to the mobile station (MS) from the first base station (BTS1) and the second base station (BTS2), and b) selecting means for selecting the second base station (BTS2) communication channel for communicating between the at least one mobile station (MS) and the second base station (BTS2) when an output from the monitoring means fulfils a predetermined criterion.
Claim 4
Dependent Claim
43 words
Apparatus according to claim 3, wherein the cellular radio telephone system further comprises at least one mobile switching centre (MSC), and the selecting means is disposed at the at least one mobile switching centre (MSC) or first or second base station (BTS1, BTS2).
Claim 5
Dependent Claim
32 words
Apparatus according to claim 4, wherein the selecting means is operable in accordance with an output from the monitoring means and transmitted to the mobile switching centre (MSC) or base station (BTS).
Claim 6
Dependent Claim
19 words
Apparatus according to claim 3, wherein the selecting means is disposed in the at least one mobile station (MS).
Claim 7
Dependent Claim
21 words
Apparatus according to any preceding claim, wherein the cellular radio telephone system is substantially a time division multiple access (TDMA) system.
Claim 8
Dependent Claim
47 words
Apparatus according to claim 7, wherein the second base station (BTS2) is adapted to communicate with the mobile station (MS) by using a different time slot to the time slot utilised by the first base station (BTS1) for communicating with the at least one mobile station (MS).
Claim 9
Dependent Claim
18 words
Apparatus according to claim 7 or claim 8, wherein a TDMA frame comprises at least eight time slots.
Claim 10
Dependent Claim
22 words
Apparatus according to any of claims 7 to 9, wherein at least the user's data is the same in different time slots.
Claim 11
Dependent Claim
52 words
Apparatus according to any of claims 2 to 10, wherein the second base station (BTS2) communicates with the at least one mobile station (MS) via a different communication channel to the communication channel utilised by the first base station (BTS1) for communicating with the mobile station (MS) for at least 0.5 seconds.
Claim 12
Dependent Claim
37 words
Apparatus according to any of claims 2 to 11, wherein communication between the base stations (BTS1, BTS2) and the at least one mobile station is buffered and combined in order to improve the quality of the communication.
Claim 13
Dependent Claim
47 words
Apparatus according to any of claims 3 to 12, wherein the predetermined criterion is that the signal to noise ratio in the second base station (BTS2) communication channel is greater than the signal to noise ratio in the communication channel utilised by the first base station (BTS1).
Claim 14
Independent Claim
94 words
A method for performing handover in a cellular radio telephone system comprising a first base station (BTS1) and a second base station (BTS2) and at least one mobile station (MS), wherein during handover of the mobile station (MS) between the first base station (BTS1) and the second base station (BTS2), the second base station (BTS2) is adapted to communicate with the at least one mobile station (MS) by utilizing a different communication channel to the communication channel utilized by the first base station (BTS1) for communicating with the at least one mobile station (MS).
Claim 15
Independent Claim
90 words
A method for enhancing handover in a digital cellular radio telephone system based on time division multiple access (TDMA) which comprises at least one center (MSC) and several base stations (BTS) and mobile stations (MS), characterized in that for the time of preparation and execution of the handover, parallel physical links are formed between the mobile station (MS) and two or more base stations (BTS1, BTS2) by using a different time slot between the mobile station (MS) and various base stations (BTS) in at least one of the communication directions.
Claim 16
Independent Claim
175 words
A method for enhancing handover in a digital cellular radio telephone system based on time division multiple access (TDMA) which comprises at least one center (MSC) and several base stations (BTS) and mobile stations (MS) and in which a) the mobile station (MS) periodically monitors the signal sent by the nearest base stations (BTS1, BTS2), and b) the mobile station (MS) is directed, on the basis of the monitoring results and predetermined criteria, to switch into a channel of another base station, for the handover, characterized in that, on the basis of the monitored results and predetermined criteria, the mobile station (MS) is directed to form links with two or more base stations (BTS1, BTS2) in parallel for the preparation of the switching of the base station by using a different time slot between the mobile station (MS) and various base stations (BTS) in at least one of the communication directions, whereby switching of the base station is implemented by switching off one channel (R1) or all other channels but the selected new channel (R2).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.