Central multiple access control for frequency hopping radio networks

• US 6,570,857 B1
• Filed: 12/15/1998
• Issued: 05/27/2003
• Est. Priority Date: 01/13/1998
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Haartsen, Jacobus, Elg, Johannes
• Primary Examiner(s): Marcelo, Melvin
• Assistant Examiner(s): MEHRA, INDER P
• Application Number:
  US09/210,594
• Time in Patent Office: 1,624 Days
• Field of Search: 370/322, 370/328-329, 370/337, 370/345-350, 370/431, 370/442, 370/449-450, 370/312-313, 370/338, 370/475, 370/375, 370/443, 370/468, 370/432, 370/321, 370/323
• US Class Current: 370/312
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system comprises a wireless master unit and one or more wireless slave units, each having a unique identifier. When a wireless slave unit is active, it is addressed by one of a limited number of temporary addresses. A PARK mode enables a wireless slave unit to be in an idle state during which its temporary address is deallocated, enabling that address to be assigned to another wireless slave unit. To page a parked slave, a paging beacon packet is broadcast to, and received by, each of the wireless slave units at fixed intervals during a master-to-slave time slot. Each wireless slave unit determines whether the received paging beacon packet includes its unique identifier. If so, the wireless slave units retrieves a temporary address from the paging beacon packet. The wireless unit transmits a response to the wireless master unit during a subsequent slave-to-master time slot if the received paging beacon packet included the unique identifier belonging to the wireless slave unit. Parked wireless slave units are also assigned a unique response number by the master. The master broadcasts a polling beacon packet during a master-to-slave time slot. If the parked slave unit desires access to the channel, it transmits a response in an N:th slave-to-master time slot following the polling beacon packet, where N is a function of the slave'"'"'s unique response number.

Claims

1. A method of operating a system comprising a wireless master unit and one or more wireless slave units, wherein each of the one or more wireless slave units has a unique identifier, the method comprising the steps of:

broadcasting a paging beacon packet to each of the one or more wireless slave units at fixed intervals during a master-to-slave time slot;

receiving the paging beacon packet in each of the one or more wireless slave units;

in each of the one or more wireless slave units, determining whether the received paging beacon packet includes the unique identifier belonging to the wireless slave unit;

in each of the one or more wireless slave units, retrieving a temporary address from the paging beacon packet if the received beacon packet included the unique identifier belonging to the wireless slave unit; and

in each of the one or more wireless slave units, transmitting a response to the wireless master unit during a subsequent slave-to-master time slot if the received paging beacon packet included the unique identifier belonging to the wireless slave unit.

2. The method of claim 1, further comprising the steps of:

in each of the one or more wireless slave units, determining whether a subsequent traffic packet from the wireless master unit includes the temporary address; and

in each of the one or more wireless slave units, transmitting a response to the wireless master unit during another subsequent slave-to-master time slot if the subsequent traffic packet from the wireless master unit includes the temporary address.

3. The method of claim 1, wherein the paging beacon packet is a type of beacon packet, wherein beacon packets have a header portion that includes a predefined temporary address that is never assigned to any of the one or more wireless slave units in the system.

4. A method of operating a system comprising a wireless master unit and one or more wireless slave units, wherein each of the one or more wireless slave units has a unique identifier, the method comprising the steps of:

defining a series of time slots comprising alternating occurrences of a master-to-slave time slot and a slave-to-master time slot, wherein each of the slave-to-master time slots comprises a plurality of slave-to-master sub-slots;

allocating a unique response number to each of the one or more wireless slave units;

broadcasting a polling beacon packet to each of the one or more wireless slave units at fixed intervals during a master-to-slave time slot;

for at least one of the one or more wireless slave units, transmitting a packet to the wireless master unit during a slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet, wherein N is a function of the unique response number of the at least one or more wireless slave units.

5. The method of claim 4, further comprising the step of for said at least one of the one or more wireless slave units, detecting whether any master activity occurred in the master-to-slave time slot immediately preceding the slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet, and

wherein the step of transmitting the packet to the wireless master unit during a slave-to-master sub-slot is performed only if no master activity was detected in the master-to-slave time slot immediately preceding the slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet.

6. The method of claim 4, further comprising the step of:

in the wireless master unit, receiving the packet from the at least one of the one or more wireless slave units; and

in the wireless master unit, determining which of the one or more wireless slave units transmitted the packet by determining which slave-to-master sub-slot the packet was received in, relative to the master-to-slave time slot during which the polling beacon packet was broadcast.

7. The method of claim 6, further comprising the steps of:

in the wireless master unit, broadcasting a paging beacon packet to the at least one of the one or more wireless slave units, wherein the paging beacon packet includes the unique identifier of the at least one of the one or more wireless slave units and a temporary address for later use in paging the at least one of the one or more wireless slave units.

8. The method of claim 4, wherein the step of allocating a unique response number to each of the one or more wireless slave units comprises:

in the wireless master unit, registering a unique identifier for each of the wireless slave units;

associating a unique response number with each of the registered unique identifiers; and

transmitting unique response numbers to the respective wireless slave units having the unique identifiers.

9. The method of claim 4, wherein the polling beacon packet is a type of beacon packet, wherein beacon packets have a header portion that includes a predefined temporary address that is never assigned to any of the one or more wireless slave units in the system.

10. The method of claim 4, wherein each of the slave-to-master sub-slots is a half slot.

11. A system comprising:

a wireless master unit; and

one or more wireless slave units, wherein each of the one or more wireless slave units has a unique identifier,

wherein;

the wireless master unit comprises;

means for broadcasting a paging beacon packet to each of the one or more wireless slave units at fixed intervals during a master-to-slave time slot; and

each of the wireless slave units comprises;

means for receiving the paging beacon packet;

means for determining whether the received paging beacon packet includes the unique identifier belonging to the wireless slave unit;

means for retrieving a temporary address from the paging beacon packet if the received beacon packet included the unique identifier belonging to the wireless slave unit; and

means for transmitting a response to the wireless master unit during a subsequent slave-to-master time slot if the received paging beacon packet included the unique identifier belonging to the wireless slave unit.

12. The system of claim 11, wherein each of the one or more wireless slave units further comprises:

means for determining whether a subsequent traffic packet from the wireless master unit includes the temporary address; and

means for transmitting a response to the wireless master unit during another subsequent slave-to-master time slot if the subsequent traffic packet from the wireless master unit includes the temporary address.

13. The system of claim 11, wherein the paging beacon packet is a type of beacon packet, wherein beacon packets have a header portion that includes a predefined temporary address that is never assigned to any of the one or more wireless slave units in the system.

14. A system comprising:

a wireless master unit; and

one or more wireless slave units, wherein each of the one or more wireless slave units has a unique identifier,

wherein;

the wireless master unit comprises;

means for defining a series of time slots comprising alternating occurrences of a master-to-slave time slot and a slave-to-master time slot, wherein each of the slave-to-master time slots comprises a plurality of slave-to-master sub-slots;

means for allocating a unique response number to each of the one or more wireless slave units; and

means for broadcasting a polling beacon packet to each of the one or more wireless slave units at fixed intervals during a master-to-slave time slot; and

each of the wireless slave units comprises;

means for transmitting a packet to the wireless master unit during a slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet, wherein N is a function of the unique response number of the at least one or more wireless slave units.

15. The system of claim 14, wherein:

each of the wireless slave units further comprises means for detecting whether any master activity occurred in the master-to-slave time slot immediately preceding the slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet, and

wherein the means for transmitting the packet to the wireless master unit during a slave-to-master sub-slot operates only if no master activity was detected in the master-to-slave time slot immediately preceding the slave-to-master sub-slot that occurs N slave-to-master sub-slots after the polling beacon packet.

16. The system of claim 14, wherein the wireless master unit further comprises:

means for receiving the packet from the at least one of the one or more wireless slave units; and

means for determining which of the one or more wireless slave units transmitted the packet by determining which slave-to-master sub-slot the packet was received in, relative to the master-to-slave time slot during which the polling beacon packet was broadcast.

17. The system of claim 16, wherein the wireless master unit further comprises:

means for broadcasting a paging beacon packet to the at least one of the one or more wireless slave units, wherein the paging beacon packet includes the unique identifier of the at least one of the one or more wireless slave units and a temporary address for later use in paging the at least one of the one or more wireless slave units.

18. The system of claim 14, wherein in the wireless master unit, the means for allocating a unique response number to each of the one or more wireless slave units comprises:

means for registering a unique identifier for each of the wireless slave units;

means for associating a unique response number with each of the registered unique identifiers; and

means for transmitting unique response numbers to the respective wireless slave units having the unique identifiers.

19. The system of claim 14, wherein the polling beacon packet is a type of beacon packet, wherein beacon packets have a header portion that includes a predefined temporary address that is never assigned to any of the one or more wireless slave units in the system.

20. The method of claim 14, wherein each of the slave-to-master sub-slots is a half slot.

21. A wireless master unit for use in a system comprising the wireless master unit and one or more wireless slave units, the wireless master unit comprising:

means for generating a beacon packet having a header portion that includes a predefined temporary address that is never assigned to the one or more wireless slave units in the system; and

means for broadcasting the beacon packet to each of the one or more wireless slave units at fixed intervals during a master-to-slave time slot.

22. A wireless slave unit for use in a system comprising a wireless master unit and one or more wireless slave units, the wireless slave unit comprising:

means for receiving a paging beacon packet that is broadcast from the wireless master unit at fixed intervals during a master-to-slave time slot;

means for determining whether the received paging beacon packet includes the unique identifier belonging to the wireless slave unit;

means for retrieving a temporary address from the paging beacon packet if the received paging beacon packet included the unique identifier belonging to the wireless slave unit; and

means for transmitting a response to the wireless master unit during a subsequent slave-to-master time slot if the received paging beacon packet included the unique identifier belonging to the wireless slave unit.

23. The wireless slave unit of claim 22, further comprising:

means for determining whether a subsequent traffic packet from the wireless master unit includes the temporary address; and

means for transmitting a response to the wireless master unit during another subsequent slave-to-master time slot if the subsequent traffic packet from the wireless master unit includes the temporary address.

24. The wireless slave unit of claim 22, wherein the paging beacon packet is a type of beacon packet, wherein beacon packets have a header portion that includes a predefined temporary address that is never assigned to any of the one or more wireless slave units in the system.