Network supporting roaming, sleeping terminals

• US 7,536,167 B2
• Filed: 07/29/2003
• Issued: 05/19/2009
• Est. Priority Date: 05/13/1991
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Luse, Ronald E., Meier, Robert C., Sojka, Marvin L., Arensdorf, Richard C., Danielson, Arvin D., Detweiler, Mary L., West, Guy J., Gollnick, Charles D., Young, Amos D., Cnossen, James D., Geers, Robert G., Spiess, Gary N., Pavek, John G., Cargin, Jr., Keith K., Mahany, Ronald L.
• Primary Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US10/630,138
• Publication Number:
  US 20040023651A1
• Time in Patent Office: 2,121 Days
• Field of Search: 4553431- 6, 455/517, 455/561, 455/412.2, 455/574
• US Class Current: 455/343.4
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices
• CPC Class Codes: H01Q 1/007 specially adapted for indoor communication
• CPC Class Codes: H04B 17/0085 using test signal generators
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0032 Without explicit signalling
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/30 for proactive routing
• CPC Class Codes: H04W 40/36 due to handover
• CPC Class Codes: H04W 52/0225 using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/029 reducing the clock frequency of the controller
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

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.

Claims

1. A radio frequency data communication system comprising:

one or more base stations each having a radio frequency transceiver and each base station transmitting a pending message list at each of selected time intervals; and

a plurality of roaming terminals each having a radio frequency transceiver, the roaming terminals being selectively communicative with one or more base stations and each of the roaming terminals selectively deactivating the terminal'"'"'s radio frequency transceiver through a plurality of the selected time intervals and synchronizing the activation of the terminal'"'"'s radio frequency transceiver to receive the pending message list following the plurality of the selected time intervals.

2. A radio frequency data communication system as recited in claim 1 wherein the one or more base stations transmits timing information regarding the selected time intervals to the plurality of roaming terminals.

3. A radio frequency data communication system as recited in claim 2 wherein the one or more base stations communicates the timing information during the selected time intervals.

4. A radio frequency data communication system as recited in claim 1 wherein the one or more base stations transmits timing information regarding the selected time intervals along with each pending message list to the plurality of roaming terminals.

5. The radio frequency data communication system of claim 1, wherein the respective transceivers of the roaming terminals are spread spectrum transceivers.

6. The radio frequency data communication system of claim 1, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

7. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to activate its transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

8. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to determine whether to consider a received pending message list transmission based, at least in part, on signal strength.

9. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals comprises a hand-held terminal.

10. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals comprises circuitry that operates to perform batch file transfer.

11. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals comprises circuitry that operates to perform on-line data entry.

12. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission.

13. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

14. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

15. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause its respective transceiver to operate in a sleep mode by, at least in part, causing circuitry to power down the transceiver.

16. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to determine a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

17. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to determine a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

18. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to determine a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

19. The radio frequency data communication system of claim 1, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

20. The radio frequency data communication system of claim 1, wherein the pending message list comprises information indicating that a message awaits delivery to at least one of the roaming terminals.

21. The radio frequency data communication system of claim 1, wherein the pending message list comprises information from which at least one of the roaming terminals determines whether a message awaits delivery to the at least one of the roaming terminals.

22. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to analyze a received pending message list to determine whether a message awaits delivery to the at least one of the roaming terminals.

23. The radio frequency data communication system of claim 1, wherein in response to a received pending message list indicating that a message awaits delivery to at least one of the roaming terminals, the at least one of the roaming terminals operates to direct its respective transceiver to transmit a message requesting delivery of one or more pending messages to the at least one of the roaming terminals.

24. The radio frequency data communication system of claim 1, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to at least one of the roaming terminals.

25. The radio frequency data communication system of claim 1, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to at least one of the roaming terminals.

26. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to maintain operation of the at least one of the roaming terminals in an awake state if a predetermined number of expected signals from the communication system are not received.

27. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to determine a number of the selected time intervals in which to operate its respective transceiver in a sleep mode.

28. The radio frequency data communication system of claim 1, wherein the pending message list comprises information of mail messages awaiting delivery to at least one of the roaming terminals.

29. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the at least one of the roaming terminals.

30. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to activate and deactivate particular circuitry of the at least one of the roaming terminals in a consistent cycle.

31. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for a first period of time if no message is received and for a second period of time, longer than the first period of time, if a message is received.

32. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals 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.

33. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for at least an entire duration of a communication session with the communication system.

34. The radio frequency data communication system of claim 1, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for a fixed time period following completion of a communication session with the communication system.

35. A radio frequency data communication system comprising:

one or more base stations each having a radio frequency transceiver and each base station transmitting a pending message list at each of selected time intervals; and

a plurality of roaming terminals each having a radio frequency transceiver, the roaming terminals being selectively communicative with one or more base stations and each of the roaming terminals selectively deactivating the terminal'"'"'s radio frequency transceiver through at least one of the selected time intervals and synchronizing the activation of the terminal'"'"'s radio frequency transceiver to receive the pending message list following at least one of the selected time intervals.

36. A radio frequency data communication system as recited in claim 35 wherein the one or more base stations transmits timing information regarding the selected time intervals to the plurality of roaming terminals.

37. A radio frequency data communication system as recited in claim 36 wherein the one or more base stations communicates the timing information during the selected time intervals.

38. A radio frequency data communication system as recited in claim 35 wherein the one or more base stations transmits timing information regarding the selected time intervals along with each pending message list to the plurality of roaming terminals.

39. The radio frequency data communication system of claim 35, wherein the respective transceivers of the roaming terminals are spread spectrum transceivers.

40. The radio frequency data communication system of claim 35, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

41. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to activate its transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

42. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to determine whether to consider a received pending message list transmission based, at least in part, on signal strength.

43. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals comprises a hand-held terminal.

44. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals comprises circuitry that operates to perform batch file transfer.

45. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals comprises circuitry that operates to perform on-line data entry.

46. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission.

47. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

48. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to calculate an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

49. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause its respective transceiver to operate in a sleep mode by, at least in part, causing circuitry to power down the transceiver.

50. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to determine a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

51. The radio frequency data communication system of claim 35, wherein at least one of the roaming tenninals operates to determine a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

52. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to determine a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

53. The radio frequency data communication system of claim 35, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

54. The radio frequency data communication system of claim 35, wherein the pending message list comprises information indicating that a message awaits delivery to at least one of the roaming terminals.

55. The radio frequency data communication system of claim 35, wherein the pending message list comprises information from which at least one of the roaming terminals determines whether a message awaits delivery to the at least one of the roaming terminals.

56. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to analyze a received pending message list to determine whether a message awaits delivery to the at least one of the roaming terminals.

57. The radio frequency data communication system of claim 35, wherein in response to a received pending message list indicating that a message awaits delivery to at least one of the roaming terminals, the at least one of the roaming terminals operates to direct its respective transceiver to transmit a message requesting delivery of one or more pending messages to the at least one of the roaming terminals.

58. The radio frequency data communication system of claim 35, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to at least one of the roaming terminals.

59. The radio frequency data communication system of claim 35, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to at least one of the roaming terminals.

60. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to maintain operation of the at least one of the roaming terminals in an awake state if a predetermined number of expected signals from the communication system are not received.

61. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to determine a number of the selected time intervals in which to operate its respective transceiver in a sleep mode.

62. The radio frequency data communication system of claim 35, wherein the pending message list comprises information of mail messages awaiting delivery to at least one of the roaming terminals.

63. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the at least one of the roaming terminals.

64. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to activate and deactivate particular circuitry of the at least one of the roaming terminals in a consistent cycle.

65. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for a first period of time if no message is received and for a second period of time, longer than the first period of time, if a message is received.

66. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals 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.

67. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for at least an entire duration of a communication session with the communication system.

68. The radio frequency data communication system of claim 35, wherein at least one of the roaming terminals operates to cause circuitry of the at least one of the roaming terminals to operate in an awake state for a fixed time period following completion of a communication session with the communication system.

69. For use in a radio frequency, data communication system having one or more base stations each transmitting a pending message list at each of selected time intervals, a roaming terminal operable in a sleep mode comprising:

a radio frequency transceiver; and

a processor selectively deactivating the transceiver through a plurality of the selected time intervals to operate the transceiver in a sleep mode and synchronizing the activation of the transceiver to receive a pending message list following the sleep mode.

70. The roaming terminal of claim 69, wherein the processor operates the transceiver to receive timing information regarding the selected time intervals from one or more base stations.

71. The roaming terminal of claim 70, wherein the processor operates the transceiver to receive the timing information during the selected time intervals.

72. The roaming terminal of claim 69, wherein the processor operates the transceiver to receive timing information regarding the selected time intervals along with each pending message list.

73. A data communication method for a communication system having one or more base stations that transmit via radio frequency a pending message list at each of selected time intervals and at least one roaming terminal having a radio frequency transceiver, the method comprising:

deactivating the roaming terminal'"'"'s transceiver in a sleep mode through a plurality of the selected time intervals; and

synchronizing the activation of the roaming terminal'"'"'s radio frequency transceiver to receive the pending message list following the sleep mode.

74. The method of claim 73, further comprising transmitting timing information regarding the selected time intervals from a base station.

75. The method of claim 73, wherein the transceiver of the roaming terminal is a spread spectrum transceiver.

76. The method of claim 73, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

77. The method of claim 73, further comprising activating the transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

78. The method of claim 73, further comprising determining whether to consider a received pending message list transmission based, at least in part, on signal strength.

79. The method of claim 73, wherein the roaming terminal comprises a hand-held terminal.

80. The method of claim 73, further comprising performing batch file transfer between the roaming terminal and a base station of the communication system.

81. The method of claim 73, further comprising performing on-line data entry with the roaming terminal.

82. The method of claim 73, further comprising calculating an expected time for a pending message list transmission.

83. The method of claim 73, further comprising calculating an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

84. The method of claim 73, further comprising calculating an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

85. The method of claim 73, wherein deactivating the roaming terminal'"'"'s transceiver comprises powering down circuitry of the transceiver.

86. The method of claim 73, further comprising determining a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

87. The method of claim 73, further comprising determining a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

88. The method of claim 73, further comprising determining a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

89. The method of claim 73, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

90. The method of claim 73, wherein the pending message list comprises information indicating that a message awaits delivery to the roaming terminal.

91. The method of claim 73, wherein the pending message list comprises information from which the roaming terminal determines whether a message awaits delivery to the roaming terminal.

92. The method of claim 73, further comprising determining from a received pending message list whether a message for the roaming terminal is awaiting delivery.

93. The method of claim 73, further comprising in response to a received pending message list indicating that a message awaits delivery to the roaming terminal, directing the transceiver to transmit a message requesting delivery of one or more pending messages to the roaming terminal.

94. The method of claim 73, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to the roaming terminal.

95. The method of claim 73, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to the roaming terminal.

96. The method of claim 73, further comprising operating the roaming terminal in an awake state if a predetermined number of expected signals from the communication system are not received.

97. The method of claim 73, further comprising determining a number of the selected time intervals in which to deactivate the transceiver.

98. The method of claim 73, wherein the pending message list comprises information of mail messages awaiting delivery to the roaming terminal.

99. The method of claim 73, further comprising causing circuitry of the roaming terminal to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the roaming terminal.

100. The method of claim 73, further comprising activating and deactivating particular circuitry of the roaming terminal in a consistent cycle.

101. The method of claim 73, further comprising operating circuitry of the roaming terminal in an awake state for a first period of time if no message is received and for a second period of time, longer than the first period of time, if a message is received.

102. The method of claim 73, further comprising operating circuitry of the roaming terminal in an awake state in response to a user input and continuing operating circuitry of the roaming terminal in the awake state for a fixed time period following the user input.

103. The method of claim 73, further comprising operating circuitry of the roaming terminal in an awake state for at least an entire duration of a communication session with the communication system.

104. The method of claim 73, further comprising operating circuitry of the roaming terminal in an awake state for a fixed time period following completion of a communication session with the communication system.

105. A method for operating a roaming terminal with a radio frequency transceiver in a data communication system, the method comprising:

deactivating the roaming terminal'"'"'s transceiver in a sleep mode through a plurality of selected time intervals during which a pending message list is transmitted;

synchronizing the activation of the roaming terminal'"'"'s radio frequency transceiver to receive a message following the sleep mode;

receiving a pending message list; and

determining from the pending message list whether a message for the roaming terminal is awaiting delivery.

106. The method of claim 105, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

107. The method of claim 105, further comprising activating the transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

108. The method of claim 105, further comprising determining whether to consider a received pending message list transmission based, at least in part, on signal strength.

109. The method of claim 105, wherein the roaming terminal comprises a hand-held terminal.

110. The method of claim 105, wherein the roaming terminal comprises circuitry that operates to perform batch file transfer.

111. The method of claim 105, wherein the roaming terminal comprises circuitry that operates to perform on-line data entry.

112. The method of claim 105, further comprising calculating an expected time for a pending message list transmission.

113. The method of claim 105, further comprising calculating an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

114. The method of claim 105, further comprising calculating an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

115. The method of claim 105, wherein deactivating the roaming terminal'"'"'s transceiver in a sleep mode comprises powering down circuitry of the transceiver.

116. The method of claim 105, further comprising determining a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

117. The method of claim 105, further comprising determining a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

118. The method of claim 105, further comprising determining a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

119. The method of claim 105, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

120. The method of claim 105, wherein the pending message list comprises information indicating that a message awaits delivery to the roaming terminal.

121. The method of claim 105, wherein the pending message list comprises information from which circuitry of the roaming terminal determines whether a message awaits delivery to the roaming terminal.

122. The method of claim 105, wherein determining from the pending message list whether a message for the roaming terminal is awaiting delivery comprises utilizing at least one processor operates to analyze the pending message list to determine whether a message for the roaming terminal is awaiting delivery.

123. The method of claim 105, further comprising in response to a received pending message list indicating that a message awaits delivery to the roaming terminal, directing the transceiver to transmit a message requesting delivery of one or more pending messages to the roaming terminal.

124. The method of claim 105, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to the roaming terminal.

125. The method of claim 105, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to the roaming terminal.

126. The method of claim 105, further comprising operating the roaming terminal in an awake state if a predetermined number of expected signals from the communication system are not received.

127. The method of claim 105, further comprising determining a number of the selected time intervals in which to deactivate the transceiver in a sleep mode.

128. The method of claim 105, wherein the pending message list comprises information of mail messages awaiting delivery to the roaming terminal.

129. The method of claim 105, further comprising causing circuitry of the roaming terminal to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the roaming terminal.

130. The method of claim 105, further comprising activating and deactivating particular circuitry of the roaming terminal in a consistent cycle.

131. The method of claim 105, further comprising operating circuitry of the roaming terminal in an awake state for a first period of time if no message is received and for a second period of time, longer than the first period of time, if a message is received.

132. The method of claim 105, further comprising operating circuitry of the roaming terminal in an awake state in response to a user input and continuing operating circuitry of the roaming terminal in the awake state for a fixed time period following the user input.

133. The method of claim 105, further comprising operating circuitry of the roaming terminal in an awake state for at least an entire duration of a communication session with the communication system.

134. The method of claim 105, further comprising operating circuitry of the roaming terminal in an awake state for a fixed time period following completion of a communication session with the communication system.

203. The method of claim 105, wherein the transceiver of the terminal is a spread spectrum transceiver.

135. For use in a radio frequency, data communication system having at least one base station that transmits a pending message list at each of selected time intervals, a roaming terminal having a radio frequency transceiver and operable in a sleep mode, the roaming terminal comprising:

at least one processor that operates to selectively deactivate a radio frequency transceiver of the roaming terminal through a plurality of the selected time intervals to operate the transceiver in a sleep mode, and synchronize activation of the transceiver to receive a pending message list following the sleep mode.

136. The roaming terminal of claim 135, wherein the at least one processor operates to control the radio frequency transceiver of the roaming terminal to receive timing information regarding the selected time intervals from one or more base stations.

137. The roaming terminal of claim 136, wherein the at least one processor operates to control the radio frequency transceiver of the roaming terminal to receive the timing information during the selected time intervals.

138. The roaming terminal of claim 135, wherein the at least one processor operates to control the radio frequency transceiver of the roaming terminal to receive timing information regarding the selected time intervals along with each pending message list.

139. The roaming terminal of claim 135, wherein the transceiver of the roaming terminal is a spread spectrum transceiver.

140. The roaming terminal of claim 135, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

141. The roaming terminal of claim 135, wherein the at least one processor operates to activate the transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

142. The roaming terminal of claim 135, wherein the at least one processor operates to determine whether to consider a received pending message list transmission based, at least in part, on signal strength.

143. The roaming terminal of claim 135, wherein the roaming terminal comprises a hand-held terminal.

144. The roaming terminal of claim 135, wherein the roaming terminal comprises circuitry that operates to perform batch file transfer.

145. The roaming terminal of claim 135, wherein the roaming terminal comprises circuitry that operates to perform on-line data entry.

146. The roaming terminal of claim 135, wherein the at least one processor operates to calculate an expected time for a pending message list transmission.

147. The roaming terminal of claim 135, wherein the at least one processor operates to calculate an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

148. The roaming terminal of claim 135, wherein the at least one processor operates to calculate an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

149. The roaming terminal of claim 135, wherein the at least one processor operates to cause the transceiver to operate in a sleep mode by, at least in part, causing circuitry to power down the transceiver.

150. The roaming terminal of claim 135, wherein the at least one processor operates to determine a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

151. The roaming terminal of claim 135, wherein the at least one processor operates to determine a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

152. The roaming terminal of claim 135, wherein the at least one processor operates to determine a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

153. The roaming terminal of claim 135, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

154. The roaming terminal of claim 135, wherein the pending message list comprises information indicating that a message awaits delivery to the roaming terminal.

155. The roaming terminal of claim 135, wherein the pending message list comprises information from which the at least one processor determines whether a message awaits delivery to the roaming terminal.

156. The roaming terminal of claim 135, wherein the at least one processor operates to analyze a received pending message list to determine whether a message awaits delivery to the roaming terminal.

157. The roaming terminal of claim 135, wherein the response to a received pending message list indicating that a message awaits delivery to the roaming terminal, the at least one processor operates to direct the transceiver to transmit a message requesting delivery of one of more pending messages to the roaming terminal.

158. The roaming terminal of claim 135, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to the roaming terminal.

159. The roaming terminal of claim 135, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to the roaming terminal.

160. The roaming terminal of claim 135, wherein the at least one processor operates to maintain operation of the roaming terminal in an awake state if a predetermined number of expected signals from the communication system are not received.

161. The roaming terminal of claim 135, wherein the at least one processor operates to determine a number of the selected time intervals in which to operate the transceiver in a sleep mode.

162. The roaming terminal of claim 135, wherein the pending message list comprises information of mail messages awaiting delivery to the roaming terminal.

163. The roaming terminal of claim 135, wherein the at least one processor operates to cause circuitry of the roaming terminal to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the roaming terminal.

164. The roaming terminal of claim 135, wherein the at least one processor operates to activate and deactivate particular circuitry of the roaming terminal in a consistent cycle.

165. The roaming terminal of claim 135, wherein the at least one processor operates to cause circuitry of the roaming terminal to operate in an awake state for a first period of time of no message is received and for a second period of time, longer than the first period of time, if a message is received.

166. The roaming terminal of claim 135, wherein the at least one processor operates to cause circuitry of the roaming 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.

167. The roaming terminal of claim 135, wherein the at least one processor operates to cause circuitry of the roaming terminal to operate in an awake state for at least an entire duration of a communication session with the communication system.

168. The roaming terminal of claim 135, wherein the at least one processor operates to cause 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.

169. A roaming terminal for use in a data communication system, the roaming terminal having a radio frequency transceiver, the roaming terminal comprising:

at least one processor that operates to, at least;

deactivate the terminal'"'"'s radio frequency transceiver in a sleep mode through a plurality of selected time intervals during which a pending message list is transmitted;

synchronize activation of the roaming terminal'"'"'s radio frequency transceiver to receive a message following the sleep mode;

receive a pending message list; and

determine from the pending message list whether a message for the roaming terminal is awaiting delivery.

170. The roaming terminal of claim 169, wherein the at least one processor operates to, at least, control the terminal'"'"'s radio frequency transceiver to receive timing information regarding the selected time intervals from one or more base stations.

171. The roaming terminal of claim 170, wherein the at least one processor operates to, at least, control the terminal'"'"'s radio frequency transceiver to receive the timing information during the selected time intervals.

172. The roaming terminal of claim 169, wherein the at least one processor operates to, at least, control the terminal'"'"'s radio frequency transceiver to receive timing information regarding the selected time intervals along with each pending message list.

173. The roaming terminal of claim 169, wherein the transceiver of the roaming terminal is a spread spectrum transceiver.

174. The roaming terminal of claim 169, wherein the communication system comprises a plurality of base stations, each of which corresponds to a respective coverage area.

175. The roaming terminal of claim 169, wherein the at least one processor operates to activate the transceiver to receive a pending message list for up to a maximum listening period, where the maximum listening period is at least a maximum expected time interval between consecutive pending message list transmissions.

176. The roaming terminal of claim 169, wherein the at least one processor operates to determine whether to consider a received pending message list transmission based, at least in part, on signal strength.

177. The roaming terminal of claim 169, wherein the roaming terminal comprises a hand-held terminal.

178. The roaming terminal of claim 169, wherein the roaming terminal comprises circuitry that operates to perform batch file transfer.

179. The roaming terminal of claim 169, wherein the roaming terminal comprises circuitry that operates to perform on-line data entry.

180. The roaming terminal of claim 169, wherein the at least one processor operates to calculate an expected time for a pending message list transmission.

181. The roaming terminal of claim 169, wherein the at least one processor operates to calculate an expected time for a pending message list transmission based, at least in part, on timing information received with a previous pending message list transmission.

182. The roaming terminal of claim 169, wherein the at least one processor operates to calculate an expected time for a pending message list transmission based, at least in part, on seed information received in a previous transmission.

183. The roaming terminal of claim 169, wherein the at least one processor operates to cause the transceiver to operate in a sleep mode by, at least in part, causing circuitry to power down the tranceiver.

184. The roaming terminal of claim 169, wherein the at least one processor operates to determine a sleep time period based, at least in part, on an expected duration of a communication between another roaming terminal and a base station of the communication system.

185. The roaming terminal of claim 169, wherein the at least one processor operates to determine a sleep time period based, at least in part, on message length information communicated between another roaming terminal and a base station of the communication system.

186. The roaming terminal of claim 169, wherein the at least one processor operates to determine a sleep time period based, at least in part, on message length information transmitted by another roaming terminal.

187. The roaming terminal of claim 169, wherein the pending message list comprises information of messages stored for a plurality of sleeping terminals.

188. The roaming terminal of claim 169, wherein the pending message list comprises information indicating that a message awaits delivery to the roaming terminal.

189. The roaming terminal of claim 169, wherein the pending message list comprises information from which the at least one processor determines whether a message awaits delivery to the roaming terminal.

190. The roaming terminal of claim 169, wherein the at least one processor operates to analyze a received pending message list to determine whether a message awaits delivery to the roaming terminal.

191. The roaming terminal of claim 169, wherein in response to a received pending message list indicating that a message awaits delivery to the roaming terminal, the at least one processor operates to direct the transceiver to transmit a message requesting delivery of one or more pending messages to the roaming terminal.

192. The roaming terminal of claim 169, wherein the pending message list comprises information indicating that one or more messages are stored at a node of the communication system and awaiting delivery to the roaming terminal.

193. The roaming terminal of claim 169, wherein the pending message list comprises information indicating that one or more messages are stored in a base station of the communication system and awaiting delivery to the roaming terminal.

194. The roaming terminal of claim 169, wherein the at least one processor operates to maintain operation of the roaming terminal in an awake state if a predetermined number of expected signals from the communication system are not received.

195. The roaming terminal of claim 169, wherein the at least one processor operates to determine a number of the selected time intervals in which to operate the transceiver in a sleep mode.

196. The roaming terminal of claim 169, wherein the pending message list comprises information of mail messages awaiting delivery to the roaming terminal.

197. The roaming terminal of claim 169, wherein the at least one processor operates to cause circuitry of the roaming terminal to enter a sleep mode for at least a portion of an expected delay to receive a message in response to a message sent from the roaming terminal.

198. The roaming terminal of claim 169, wherein the at least one processor operates to activate and deactivate particular circuitry of the roaming terminal in a consistent cycle.

199. The roaming terminal of claim 169, wherein the at least one processor operates to cause circuitry of the roaming terminal to operate in an awake state for a first period of time if no message is received and for a second period of time, longer than the first period of time, if a message is received.

200. The roaming terminal of claim 169, wherein the at least one processor operates to cause circuitry of the roaming 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.

201. The roaming terminal of claim 169, wherein the at least one processor operates to cause circuitry of the roaming terminal to operate in an awake state for at least an entire duration of a communication session with the communication system.

202. The roaming terminal of claim 169, wherein the at least one processor operates to cause 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.