Establishment of multiple low-rate inbound signaling links in CDMA dispatch system
First Claim
1. In a CDMA dispatch communication system comprising a fixed infrastructure and a plurality of subscribers units engaged in a group call wherein at least a plurality of group members, including a second group member, are listening to the group call on the same outbound link from the fixed infrastructure, and wherein a first group member is transmitting a signal on an inbound link to the fixed infrastructure, a method of establishing multiple low-rate inbound links comprising the fixed infrastructure performed steps of:
- detecting a request by the subscriber unit of the first group member for a group call;
establishing a full-rate traffic inbound link with the subscriber unit of the first group member for transmitting a signal to the fixed infrastructure;
establishing a full-rate traffic outbound link with the subscriber units of each of the at least a plurality of group members so they can receive the signal from the fixed infrastructure; and
prior to transmitting the signal from the first group member to the fixed infrastructure, establishing for each the at least a plurality of group members, including the second group member, a low-rate inbound link, different from said full-rate traffic inbound link, for receiving at least one of forward power control information, soft hand-off information and reverse power information therefrom.
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Accused Products
Abstract
A quality dispatch service on a CDMA based wireless system. To achieve spectral efficiency and fast access for follow-up calls, in response to a request by a talkgroup member to have a group call established, the non-requesting (listening-only) members are allowed to establish a low-rate (non-voice) signaling link in the reverse direction (inbound) for the limited purpose of (i) providing forward power control information to the fixed infrastructure; (ii) requesting soft hand-off when required; and (iii) maintaining the correct reverse link power control to allow for fast channel access for a follow-on call. In accordance with the illustrative embodiment, the establishment of low-rate inbound signaling links occurs prior to beginning the voice communications. Because a low-rate signaling link, as contemplated by the present invention, is a non-voice link which signals at a predetermined rate substantially less than that of a full-rate traffic link, proportionately less average power is required for dispatch communications than would otherwise be the case if full-rate traffic links were provided instead to non-talking talkgroup members. The present solution results in less interference to the CDMA system and thus substantially less impact on overall system capacity.
63 Citations
15 Claims
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1. In a CDMA dispatch communication system comprising a fixed infrastructure and a plurality of subscribers units engaged in a group call wherein at least a plurality of group members, including a second group member, are listening to the group call on the same outbound link from the fixed infrastructure, and wherein a first group member is transmitting a signal on an inbound link to the fixed infrastructure, a method of establishing multiple low-rate inbound links comprising the fixed infrastructure performed steps of:
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detecting a request by the subscriber unit of the first group member for a group call; establishing a full-rate traffic inbound link with the subscriber unit of the first group member for transmitting a signal to the fixed infrastructure; establishing a full-rate traffic outbound link with the subscriber units of each of the at least a plurality of group members so they can receive the signal from the fixed infrastructure; and prior to transmitting the signal from the first group member to the fixed infrastructure, establishing for each the at least a plurality of group members, including the second group member, a low-rate inbound link, different from said full-rate traffic inbound link, for receiving at least one of forward power control information, soft hand-off information and reverse power information therefrom. - View Dependent Claims (2, 3, 4, 5)
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6. In a CDMA dispatch communication system comprising a fixed infrastructure and a plurality of subscribers units engaged in a group call wherein at least a plurality of group members, including a second group member, are listening to the group call on the same outbound link from the fixed infrastructure, and wherein a first group member is transmitting a signal on an inbound link to the fixed infrastructure, a method of establishing a low-rate inbound link, the method comprising the subscriber unit performed steps of:
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receiving notification from the fixed infrastructure that a group call is being setup; establishing a full-rate traffic outbound link for monitoring signals transmitted from the fixed infrastructure; and prior to receiving the signal from the fixed infrastructure on the full-rate traffic outbound link, establishing a low-rate inbound link, different from said full-rate traffic inbound link, for communicating at least one of forward power control information, soft hand-off information and reverse power information to the fixed infrastructure. - View Dependent Claims (7, 8)
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9. A fixed infrastructure for facilitating CDMA dispatch service among a plurality of subscribers units engaged in a group call wherein at least a plurality of group members, including a second group member, are listening to the group call on the same outbound link from the fixed infrastructure when a first group member is transmitting a signal on an inbound link to the fixed infrastructure, the fixed infrastructure comprising:
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means for detecting a request by the subscriber unit of the first group member for a group call; means for establishing a full-rate traffic inbound link with the subscriber unit of the first group member; means for establishing a full-rate traffic outbound link with the subscriber units of each of the other group members so they can receive the signal from the first group member; and means for establishing for each of said at least a plurality of group members, including the second group member, and prior to transmitting the signal from the first group member to the group members, a low-rate inbound link, different from said full-rate traffic inbound link, for receiving at least one of forward power control information, soft hand-off information and reverse power information from each group member. - View Dependent Claims (10, 11, 12, 13)
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14. A subscriber unit for use with a CDMA dispatch communication system having a fixed infrastructure providing dispatch service among a plurality of subscribers units engaged in a group call wherein at least a plurality of group members, including a second group member, are listening to the group call on the same outbound link from the fixed infrastructure when a first group member is transmitting a signal on an inbound link to the fixed infrastructure, the subscriber unit comprising:
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means for receiving notification from the fixed infrastructure that a group call is being setup; means for establishing a full-rate traffic outbound link for monitoring signals transmitted from the fixed infrastructure; and means for establishing a low-rate inbound link, different from said full-rate traffic inbound link, and prior to receiving the signal from the fixed infrastructure on the full-rate traffic outbound link, for communicating at least one of forward power control information, soft hand-off information, and reverse power information to the fixed infrastructure. - View Dependent Claims (15)
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Specification