Motorola Corporation

Other

Victor H Cutler, Jr

Gerald Joseph Davieau

Keith Andrew Olds

Peter J Richetta

Daniel Richard Tayloe

Kenneth M Peterson

Kenneth P Young

Dennis Paul Diekelman

Yih Guang Jan

Jim E Helm

Henry Joseph Happ, Iii

James T Stackman

A method and apparatus for controlling the initiation of new user communication links in a communication system (10), by evaluating the present in-use resources in a particular cell against reserved resources for servicing handoff communications from neighboring cells, evaluating total in-use resources of satellite (12), and determining if present conditions in satellite (12) exceed defined parameters thus inhibiting access by new users. A status is posted and transmitted in a broadcast channel (18) for subscriber units (26) to evaluate prior to initiating requests for communication services.

Method and system for managing the initiation of new traffic in a

The system (10) and method (100) adjust reuse units when nodes (e.g., satellites (20, 22)) move in a communication system (10), such as satellites (20,22) moving in their orbits around the earth in a space-based communication system (10). The method (100) and system (10) computes interference potentials between a reference reuse unit in a first reuse unit table of a first satellite (20) and reuse units being used in second reuse unit tables in second satellites (20) that are adjacent to the first satellite (20); and when the interference potentials is less than a predetermined threshold, then assigns the satellite a non-interfering reuse unit for the specific time interval.

Space-based communication system and method with continuous channel

In a communication system (10) having at least one control center (24) and multiple satellites (12), the satellites (12) operate according to tables (80), wherein each satellites table becomes obsolete at a known time referred to as the exhaustion time. The earliest exhaustion time of all satellites (12) is determined and sent to the satellites (12) in the form of a message or a time-tagged update table (150). When the earliest exhaustion time is reached without updating the satellite (12), the satellites (12) enter default operation at that earliest exhaustion time. The satellites (12) continue default operations until otherwise instructed by the control center (24).

Method and apparatus for default node operation in a multi-nodal

A cellular communication system (10) requests from subscriber units (30) to volunteer for handoff when a call resource shortage is about to occur. The subscriber units (30) may volunteer to handoff to another cell (24) depending on whether any adjacent or neighbor cell (24) provides adequate signal strength for servicing the on-going call. If there is another adjacent or neighbor cell (24) which provides adequate signal strength, the subscriber unit (30) can volunteer for handoff to the other cell. The cellular communication system (10) may accept the volunteer handoff request, whereby the subscriber unit (30) volunteering for handoff is handed-off to the other cell (24). However, the cellular communication system (10) may deny the handoff request. If the handoff request is denied, the subscriber unit (30) may have to drop the call or try to locate another cell to handoff its call before a predetermined amount of time expires.

Methods of requesting volunteers for handoff in a cellular system

A satellite cellular communication system includes satellites in motion that project cells upon the surface of the Earth. These cells are in motion and pass over individual subscriber units (26) engaged in communications, thus requiring individual subscriber units (26) to perform handoffs as an active current cell (300) currently servicing them advances. Selection of a subsequent servicing cell requires evaluation of active neighboring cells. A pre-computation of candidate cells is performed in advance according to a cell activation schedule. Active neighboring cells of an active current cell (300) are evaluated and prioritized in advance of individual subscriber unit's need for them. A candidate handoff cell list is then delivered to a satellite (12). A candidate handoff cell list is broadcast to all individual subscriber units (26) located within active current cell (300) for use in handoff decisions.

Method of pre-computation of candidate handoff cell list for cellular

Methods efficiently assign user channels in a LEO (low-earth orbit) telecommunication system. These methods adapt the channel reuses based on system load or demand. These methods achieve high capacity and minimize interference for the particular situation. Since these methods are adaptive, they adjust to maintain efficient operation as the load conditions change.

Methods of demand-based adaptive channel reuse for telecommunications

A method and apparatus for controlling communication channel allocation in a communication system (10) by obtaining (405) statistical system performance data, determining (415, 420) by a processor (815) an optimum number of sub-time slots (505, 615) and an optimum number of sub-subbands (605), generating (430) available signal transmission units from data describing historical communication traffic, and assigning (435) available signal transmission units by another processor (910) to dynamically control communication traffic.

Method and apparatus for signal transmission in a communication system

A subscriber unit (30) operates in a synchronous communication system having dynamic nodes such as satellites (12). Satellites (12) employ a strict transmit and receive time window and all transmissions directed to satellites (12) must fall within the receive window to be recognized. In a dynamic communication system where low earth orbit satellites (12) continuously orbit, propagation timing between a satellite (12) and a subscriber unit (30) vary rapidly over a wide range. Subscriber unit (30) must approximate a transmit timing advance for use in inaugurating a transmission to satellite (12). Subscriber unit (30) utilizes a valid geolocation position when available but when a position is unavailable or stale, relies on configuration characteristics of the constellation for generating an initial approximation of propagation delay.

Method and apparatus for approximating propagation delay for use in

A method and apparatus for controlling communication channel access in a communication system (10) determines channel allocations (106) which represent limits on communication channel access and conforms operations of the system (10) to the channel allocations. The channel allocations are determined by dividing a surface which emanates signals from communication units (26) into elemental areas, collecting past traffic data (102) describing past communication channel usage by the communication units (26) located in the elemental areas, generating a traffic model (104) for a future time interval based on the past traffic data, and determining the channel allocations (106) based on the traffic model.

Statistically robust traffic modeling method and apparatus

A method and apparatus for establishing communication links between communication units that travel in different, determinable directions. The method includes the steps of calculating communication link boundary corridors, generating operational plans that inform the communication units how to establish and maintain a communication link, transmitting the operational plans to the communication units, and establishing links according to the operational plans. The apparatus includes a control segment that generates the operational plans and transmits them to the communication units.

Method and apparatus for establishing communication links between

In a system that includes a constellation of satellite communication nodes, information packets are routed through the constellation using routing tables stored in each communication node. When a packet is received at a node, the packet's destination and routing table ID are read. One of several routing tables are selected using a mapping table. Each of the several routing tables has a different routing instruction set. The packet is routed away from the node using the selected routing table. When system traffic is heavy, or some of the communication links are overloaded or have failed, routing table control bits are sent to the nodes updating the mapping table. Packets are subsequently routed using different sets of routing tables, such as ones having greater hop counts.

Packet routing system and method with quasi-real-time control

A method and apparatus for balancing data packet routing through a communication system (10) and for routing data packets based on their type is accomplished by using multiple routing table pages (152, 154) and page maps (180, 190) stored in nodes (100-112). For a given data packet type, a first page map (180) is used to select a routing table page (152, 154) so that only certain types of data may be routed through a target node (100). In a test mode, a neighboring node (102-112) will be configured such that it can route test data packets through the target node (100) while not routing other types of data packets through the target node (100). For a given routing number, a second page map (190) is used to select a routing table page (152, 154) so that traffic loads are balanced throughout the system (10).

Data routing method and apparatus for communication systems having

In a system that includes a constellation of satellite communication nodes, information packets are routed through the constellation using routing tables stored in each communication node. The routing tables are generated and updated regularly to reflect anticipated traffic loading and physical changes in node connectivity within the constellation which occur as a result of satellite motion and link failures. The table generating process performs a routing simulation using historical traffic data. Forward and reverse link usage for data packets headed for the same destination are identified and canceled. New routes are then generated. Popularity ratios are formed at each exit link for each destination node based on the new routes. Several routing tables are generated for each node based on selected packet splitting numbers and the popularity ratios. The routing tables are sent to each communication node for use during the next twenty-four hour period. A routing table is selected based the least significant bits of the packet's logical channel number.

Waste canceling packet routing system and method

Information packets are routed among a constellation of satellite nodes in a communication system in a distributed, yet systematic fashion. Routing tables for each node are generated in advance by a recursive process that considers link usage and anticipated link loading for different times and states of the constellation. Routing tables are generated centrally, distributed to, and maintained in each satellite node. The routing tables are updated regularly to reflect anticipated traffic loading and physical changes in node connectivity within the constellation which occur as a result of satellite motion. The tables are also updated responsively to reflect changes in network connectivity which occur because of failures that may occur in the cross-links or satellite nodes.

Packet routing system and method therefor

A communication system (10) communicates real time data through a channel (26) that imposes delays of variable duration on signals propagating therethrough. The channel (26) may be established between a fastmoving satellite (14) in an orbit (28) around the earth and a subscriber unit (24) located proximate the earth' surface. The real time data are generated synchronously (124) at the subscriber unit (24) with a TDM frame (40) established by the satellite (14). The data are delayed in a variable delay circuit (68) before transmission through the channel (26). The duration of the delay imposed by the delay circuit (68) varies in response to timing data received from the satellite (14). The timing data describe a changing propagation delay for the channel (26) and changing definitions for TDM time slots (42', 44') Data received at the subscriber unit (24) are delayed in another variable delay circuit (76). Both gradual and abrupt timing characteristics of the channel (26) are absorbed by the variable timing circuits (68, 76).

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Mesa, AZ, United States of America

Victor H Cutler, Jr