Communication network terminal with sleep capability
View Patent ↗Improved apparatus for a radio communication system having a multiplicity of mobile transceiver units selectively in communication with a plurality of base transceiver units which, in turn, communicate with one or more host computers for storage and manipulation of data collected by bar code scanners or other collection means associated with the mobile transceiver units. A network controller and an adapter which has a simulcast and sequential mode provide selective interface between host computers and base transceivers. A scheme for routing data through the communication system is also disclosed wherein the intermediate base stations are organized into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Additionally, redundant network and communication protocol is disclosed wherein the network utilizes a polling communication protocol which, under heavy loaded conditions, requires that a roaming terminal wishing to initiate communication must first determine that the channel is truly clear by listing for an entire interpoll gap time. In a further embodiment, a criterion used by the roaming terminals for attaching to a given base station reduces conflicts in the overlapping RF regions of adjacent base stations.
1. A terminal for use in a wireless. communication system in which a periodic timeslot at a substantially constant period is generally reserved for a particular type of packet, the terminal comprising:
at least one processor operable to, at least:
deactivate communication circuitry of the terminal in a sleep mode through a plurality of the substantially constant periods;
synchronize activation of the communication circuitry from the sleep mode to receive a packet transmitted in the periodic timeslot; and
determine from at least the received packet whether to return the communication circuitry to the sleep mode.
2. The terminal of claim 1 , wherein the at least one processor is operable to synchronize operation of the terminal to the received packet.
3. The terminal of claim 1 , wherein the particular type of packet comprises information descriptive of the timing of future periodic timeslots.
4. The terminal of claim 1 , wherein the at least one processor is operable to control the communication circuitry to receive timing information regarding the substantially constant period.
5. The terminal of claim 1 , wherein the communication circuitry of the terminal comprises spread spectrum communication circuitry.
6. The terminal of claim 1 , wherein the at least one processor is operable to activate the communication circuitry to receive the packet transmitted in the periodic timeslot for up to a maximum listening period, where the maximum listening period is at least the substantially constant period.
7. The terminal of claim 1 , wherein the at least one processor is operable to determine whether to consider the received packet based, at least in part, on signal strength.
8. The terminal of claim 1 , wherein the terminal is battery-operated.
9. The terminal of claim 1 , wherein the terminal is portable.
10. The terminal of claim 1 , wherein the at least one processor is operable to calculate an expected time for transmission of the packet in the periodic timeslot.
11. The terminal of claim 1 , wherein the at least one processor is operable to calculate an expected time for transmission of the packet in the periodic timeslot based, at least in part, on timing information received in a previously received packet.
12. The terminal of claim 1 , wherein the at least one processor is operable to cause the communication circuitry to operate in a sleep mode by, at least in part, causing the communication circuitry to be powered down.
13. The terminal of claim 1 , wherein the at least one processor is operable to determine a sleep time period based, at least in part, on an expected duration of a current communication.
14. The terminal of claim 1 , wherein the at least one processor is operable to determine a sleep time period based, at least in part, on message length information communicated by another terminal.
15. The terminal of claim 1 , wherein the at least one processor is operable to analyze at least the received packet to determine whether to remain awake to receive one or more additional packets.
16. The terminal of claim 1 , wherein the at least one processor is operable to analyze at least the received packet to determine whether to transmit a message to a node of the communication system in response to the received at least one packet.
17. The terminal of claim 1 , wherein the at least one processor is operable to analyze at least the received packet to determine whether one or more messages are stored in a node of the communication system and awaiting delivery to the terminal.
18. The terminal of claim 1 , wherein the at least one processor is operable to analyze at least the received packet to determine whether a node of the communication system desires further communication with the terminal.
19. The terminal of claim 1 , wherein the at least one processor is operable to maintain operation of the terminal in an awake state if a predetermined number of expected packets from the communication system are not received.
20. The terminal of claim 1 , wherein the at least one processor is operable to determine a number of the substantially constant periods in which to operate the communication circuitry in a sleep mode.
21. The terminal of claim 1 , wherein the at least one processor is operable to deactivate communication circuitry of the terminal in a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the terminal.
22. The terminal of claim 1 , wherein the at least one processor is operable to cause communication circuitry of the terminal to operate in an awake state in response to a user input and to continue to operate in the awake state for a fixed time period following the user input.
23. The terminal of claim 1 , wherein the at least one processor is operable to cause communication circuitry of the roaming terminal to operate in an awake state for a fixed time period following completion of a communication session with the communication system.
24. The terminal of claim 1 , wherein the packet transmitted in the periodic timeslot comprises a HELLO packet.
25. The terminal of claim 1 , wherein all packets communicated in the periodic timeslot are of the particular type of packet.
26. The terminal of claim 1 , wherein the at least one processor is operable to determine when to activate the communication circuitry from the sleep mode based, at least in part, on an address of a node of the wireless communication system.
27. The terminal of claim 1 , wherein the at least one processor is operable to determine a pseudo-randomized transmission characteristic of a packet transmitted in the periodic timeslot based, at least in part, on an address of a node of the wireless communication system.
28. The terminal of claim 1 , wherein the at least one processor is operable to determine transmission timing characteristics of the packet transmitted in the periodic timeslot based on information communicated in a previous packet transmitted in the periodic timeslot.
29. The terminal of claim 1 , wherein the packet transmitted in the period timeslot is a broadcast message.
30. The terminal of claim 1 , wherein the particular type of packet is a beacon packet.
31. A method for operating a terminal in a communication system in which a periodic timeslot at a substantially constant period is generally reserved for a particular type of packet, the method comprising:
deactivating communication circuitry of the terminal in a sleep mode through a plurality of the substantially constant periods;
synchronizing activation of the communication circuitry from the sleep mode to receive a packet transmitted in the periodic timeslot; and
determining from at least the received packet whether to return the communication circuitry to the sleep mode.
32. The method of claim 31 , further comprising synchronizing operation of the terminal to the received packet.
33. The method of claim 31 , wherein the particular type of packet comprises information descriptive of the timing of future periodic timeslots.
34. The method of claim 31 , further comprising controlling the communication circuitry to receive timing information regarding the substantially constant period.
35. The method of claim 31 , wherein the communication circuitry of the terminal comprises spread spectrum communication circuitry.
36. The method of claim 31 , further comprising activating the communication circuitry to receive the packet transmitted in the periodic timeslot for up to a maximum listening period, where the maximum listening period is at least the substantially constant period.
37. The method of claim 31 , further comprising determining whether to consider the received packet based, at least in part, on signal strength.
38. The method of claim 31 , wherein the terminal is battery-operated.
39. The method of claim 31 , wherein the terminal is portable.
40. The method of claim 31 , further comprising calculating an expected time for transmission of the packet in the periodic timeslot.
41. The method of claim 31 , further comprising calculating an expected time for transmission of the packet in the periodic timeslot based, at least in part, on timing information received in a previously received packet.
42. The method of claim 31 , further comprising causing the communication circuitry to operate in a sleep mode by, at least in part, causing the communication circuitry to be powered down.
43. The method of claim 31 , further comprising determining a sleep time period based, at least in part, on an expected duration of a current communication.
44. The method of claim 31 , further comprising determining a sleep time period based, at least in part, on message length information communicated by another terminal.
45. The method of claim 31 , further comprising analyzing at least the received packet to determine whether to remain awake to receive one or more additional packets.
46. The method of claim 31 , further comprising analyzing at least the received packet to determine whether to transmit a message to a node of the communication system in response to the received at least one packet.
47. The method of claim 31 , further comprising analyzing at least the received packet to determine whether one or more messages are stored in a node of the communication system and awaiting delivery to the terminal.
48. The method of claim 31 , further comprising analyzing at least the received packet to determine whether a node of the communication system desires further communication with the terminal.
49. The method of claim 31 , further comprising maintaining operation of the terminal in an awake state if a predetermined number of expected packets from the communication system are not received.
50. The method of claim 31 , further comprising determining a number of the substantially constant periods in which to operate the communication circuitry in a sleep mode.
51. The method of claim 31 , further comprising deactivating communication circuitry of the terminal in a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the terminal.
52. The method of claim 31 , further comprising causing communication circuitry of the terminal to operate in an awake state in response to a user input and to continue to operate in the awake state for a fixed time period following the user input.
53. The method of claim 31 , further comprising causing communication circuitry of the roaming terminal to operate in an awake state for a fixed time period following completion of a communication session with the communication system.
54. The method of claim 31 , wherein the packet transmitted in the periodic timeslot comprises a HELLO packet.
55. The method of claim 31 , wherein all packets communicated in the periodic timeslot are of the particular type of packet.
56. The method of claim 31 , further comprising determining when to activate the communication circuitry from the sleep mode based, at least in part, on an address of a node of the wireless communication system.
57. The method of claim 31 , further comprising determining a pseudo-randomized transmission characteristic of a packet transmitted in the periodic timeslot based, at least in part, on an address of a node of the wireless communication system.
58. The method of claim 31 , further comprising determining transmission timing characteristics of the packet transmitted in the periodic timeslot based on information communicated in a previous packet transmitted in the periodic timeslot.
59. The method of claim 31 , wherein the packet transmitted in the period timeslot is a broadcast message.
60. The method of claim 31 , wherein the particular type of packet is a beacon packet.