Patent EP0522276A2 successfully refreshed from Google Patents.
EP0522276A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Channel assignment method in mobile communication system
Assignee: NEC Corp
•
Filing: 1992-05-29
•
Granted: —
•
Expires: 2012-05-29
Abstract
Abstract In a channel assignment method for a mobile communication system, each of base stations respectively arranged in a plurality of cells constituting a service area selects one of all speech communication channels in an order of priority common to all the cells in response to a speech communication request from a mobile station. The base station then checks whether the carrier to interference ratio of the selected speech communication channel is equal to or higher than a predetermined level. The selected channel is assigned as a speech communication channel for the cell when it is determined on the basis of the check result that the carrier to interference ratio is equal to or higher than the predetermined level.
Inventors
- 👤 Toshihito C/O Nec Corporation Kanai
- 👤 Kojiro C/O Nec Corporation Hamabe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 10:44
CPC Classifications
H; H04; H04W; H04W16/00; H04W16/02; H04W16/04; H04W36/00; H04W36/16; H04W36/22; H04W36/24; H04W36/32; H04W36/324; H04W72/00; H04W72/50; H04W72/54; H04W72/541; H04W72/542; H04W16/06; H04W16/10; H04W16/12; H04W16/14; H04W36/06; H04W72/56
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
133 words
A channel assignment method for a mobile communication system, characterized by comprising the steps of: causing each of base stations (1201, 1202) respectively arranged in a plurality of cells (1205, 1206) constituting a service area, in response to a speech communication request from a mobile station (1203, 1204), to select (S103, S104) one of all speech communication channels in an order of priority common to all the cells; causing the base station to check (S105, S107) whether a carrier to interference ratio of the selected speech communication channel is not less than a first level (LV1); and assigning (S108) the channel as a speech communication channel for the cell when it is determined on the basis of the check result that the carrier to interference ratio is not less than the first level.
Claim 2
Dependent Claim
35 words
A method according to claim 1, wherein the step of causing each of base stations to select one of all speech communication channels includes the step of sequentially selecting (S104) only free speech communication channels.
Claim 3
Dependent Claim
40 words
A method according to claim 1 or 2, wherein the step of assigning the channel includes the step of assigning a speech communication channel when both upstream and downstream carrier to interference ratios are not less than the first level.
Claim 4
Independent Claim
100 words
A method according to any of claims 1 to 3, further comprising the steps of: periodically receiving and storing an upstream interference level (Uup(i)) of a speech communication channel; storing (S100) an upstream carrier level (Dup) in response to a speech communication request; obtaining (S101) a propagation loss (L) by subtracting the carrier level from transmission power (P MS ) of a mobile station; obtaining (S102) a carrier level (Ddown) of the mobile station by subtracting the propagation loss from transmission power of a base station; and measuring (S106) a downstream interference level (Udown(i)) of a selected speech communication channel.
Claim 5
Independent Claim
142 words
A method according to any of claims 1 to 4, further comprising the steps of: monitoring signal quality of a currently used speech communication channel; checking (S200) whether the monitored signal quality is less than a second level (LV2); selecting (S204, S205, S211) a free speech communication channel of all the speech communication channels in accordance with the common order of priority when it is determined on the basis of the check result that the signal quality is less than the second level; checking (S208) whether a carrier to interference ratio of the selected channel is not less than a third level (LV3); and switching (S209) the currently used speech communication channel to the selected speech communication channel when it is determined on the basis of the check result that the carrier to interference ratio is not less than the third level.
Claim 6
Dependent Claim
53 words
A method according to claim 5, wherein if a loss probability within a predetermined period of time is less than a specific value, the first and third levels are increased (S302, S303), and if the loss probability is not less than the specific value, the first and third levels are decreased (S304, S305).
Claim 7
Dependent Claim
36 words
A method according to claim 5 or 6, wherein if a channel switching count within a predetermined period of time is not less than a specific value, the first and third levels are increased (S402, S403).
Claim 8
Independent Claim
113 words
A method according to any of claims 5 to 7, wherein a number of times (M) that the signal quality of the currently used speech communication channel becomes less than the second level and any other free channel having a carrier to interference ratio of not less than the third level is not found within a predetermined period of time is measured (S500), so that if the number of times is not less than a specific value, a difference between the first and third levels is increased (S502, S503), and if the number of times is less than the specific value, the difference between the first and third levels is decreased (S504, S505).
Claim 9
Independent Claim
80 words
A method according to any of claims 5 to 8, wherein a number of times (K) that the signal quality of the currently used speech communication channel becomes less than a minimum allowable level within a predetermined period of time is measured, so that if the number of times is not less than a specific value, the second level is increased (S602), and if the number of times is less than the specific value, the second level is decreased (S603).
Claim 10
Independent Claim
81 words
A method according to any of claims 5 to 9, wherein if a carrier to interference ratio of an arbitrary currently used speech communication channel is not less than a fourth level (LV4) (S706, S708) and at least one free channel having a priority higher than that of the currently used speech communication channel exists (S705, S711), the currently used speech communication channel is switched (S704, S709, S710) to one of the free speech communication channels which has the highest priority.
Claim 11
Dependent Claim
56 words
A method according to claim 10, wherein upstream carrier reception levels of all currently used speech communication channels are measured at an arbitrary timing (S800), and an order of selection of the currently used speech communication channels is specified by selecting (S802) the currently used speech communication channels in an order to decrease the reception levels.
Claim 12
Dependent Claim
41 words
A method according to claim 10 or 11, wherein an order of selection of the currently used speech communication channels is specified by selecting (S901, S902) the currently used speech communication channels in an order of priority at an arbitrary timing.
Claim 13
Independent Claim
52 words
A method according to any of claims 10 to 12, wherein if a loss probability (Pb) within a predetermined period of time is less than a specific value, the fourth level is increased (S1002), and if the loss probability is not less than the specific value, the fourth level is decreased (S1003).
Claim 14
Independent Claim
36 words
A method according to any of claims 10 to 13, wherein if a channel switching count (N) within a predetermined period of time is not less than a specific value, the fourth level is increased (S1102).
Claim 15
Independent Claim
51 words
A method according to any of claims 1 to 14, wherein each of the plurality of cells selects first the same speech communication channel which is arbitrarily set, and sequentially selects speech communication channels in an order to increase a difference in carrier frequency from the speech communication channel selected first.
Claim 16
Dependent Claim
28 words
A method according to claim 15, wherein the same speech communication which is arbitrarily set and selected first is a speech communication channel having the highest carrier frequency.
Claim 17
Dependent Claim
28 words
A method according to claim 15, wherein the same speech communication which is arbitrarily set and selected first is a speech communication channel having the lowest carrier frequency.
Claim 18
Independent Claim
45 words
A method according to any of claims 15 to 17, wherein each of the plurality of cells sequentially selects speech communication channels in an order to decrease a difference in carrier frequency from a central value of carrier frequencies of all the speech communication channels.
Claim 19
Dependent Claim
138 words
A channel assignment method for a mobile communication system, characterized by comprising the steps of: classifying a plurality of speech communication channels, assigned to perform radio communication between base stations respectively arranged in a plurality of cells constituting a service area and mobile stations in the cells, into first and second groups; classifying speech communication channels of the second group into a plurality of subgroups; allowing each of the base stations to use speech communication channels belonging to the first group and speech communication channels belonging to one of the subgroup in the second group; and causing each of the base stations to assign one of the speech communication channels belonging to the first group and one of the subgroups in the second group, which are allowed to be used, to a corresponding one of the mobile stations.
Claim 20
Dependent Claim
54 words
A method according to claim 19, wherein the base station selects (S1401) one of the first group and one subgroup of the second group, which are allowed to be used, in accordance with a type of the mobile station, and assigning (S1402, S1403) one of the speech communication channels belonging to the selected group.
Claim 21
Dependent Claim
69 words
A method according to claim 19 or 20, wherein the base station selects (S1503, S1504) one of the first group and one subgroup of the second group, which are allowed to be used, in accordance with an amount of change in propagation loss (L1, L2) between the base station and the mobile station, and assigning (S1502, S1504, S1506) one of the speech communication channels belonging to the selected group.
Claim 22
Independent Claim
58 words
A method according to any of claims 19 to 21, wherein the base station selects (S1602, S1604) one of the first group and the subgroup, which are allowed to be used, in accordance with a traveling speed (v) of the mobile station, and assigning (S1601, S1603, S1604) one of the speech communication channels belonging to the selected group.
Claim 23
Independent Claim
41 words
A method according to any of claims 19 to 22, wherein a speech communication channel to be assigned in response to a speech communication request is selected (S1700) from the speech communication channels belonging to one subgroup of the second group.
Claim 24
Independent Claim
55 words
A method according to any of claims 19 to 23, wherein channel switching is performed (S1801, S1804) between speech communication channels belonging to the first group and speech communication channels belonging to one subgroup of the second group in accordance with a use rate (u) of the speech communication channels belonging to the second group.
Claim 25
Dependent Claim
263 words
A channel assignment method for a mobile communication system in which a service area is constituted by a plurality of cells respectively having base stations arranged therein, and radio speech communication channels are set between the base station and mobile stations in each cell to perform communication, characterized by comprising the steps of: sequentially selecting (S103, S104, S110) free speech communication channels from all speech communication channels, in response to speech communication requests, in an order of priority common to all the cells; checking (S105, S107) whether a carrier to interference ratio of the selected speech communication channel is not less than a first level (LV1); assigning (S108) the speech communication channel if it is determined on the basis of the check result that the carrier to interference ratio is not less than the first level; monitoring signal quality of a currently used speech communication channel; checking (S200) whether the monitored signal quality is less than a second level (LV2); selecting (S204, S205, S211) a free speech communication channel from all the speech communication channels in the common order of priority if it is determined on the basis of the check result that the signal quality is less than the second level; checking (S208) whether a carrier to interference ratio of the selected speech communication channel is not less than a third level (LV3); and switching (209) the currently used speech communication channel to the selected speech communication channel if it is determined on the basis of the check result that the carrier to interference ratio is not less than the third level.
Claim 26
Dependent Claim
121 words
A channel assignment method for a mobile communication system in which each of base stations respectively arranged in a plurality of cells sequentially selects speech communication channels from a plurality of speech communication channels having equal carrier frequency intervals in response to speech communication requests from mobile stations, and assigning a selected speech communication channel if a carrier to interference ratio of the speech communication channel is not less than a predetermined value, characterized by comprising the steps of: selecting first the same speech communication channel which is arbitrarily set by the plurality of cells; and sequentially selecting speech communication channels in an order to decrease a difference in carrier frequency from a carrier frequency of the selected speech communication channel.
Claim 27
Dependent Claim
19 words
Mobile communication system adapted for carrying out the channel assignment method according to any of claims 1 to 26.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.