Method and apparatus for efficient bandwidth utilization for subscriber unit initialization and synchronization in a time-synchronized communication system
View Patent ↗A bandwidth efficient subscriber unit initialization and synchronization method and apparatus is described. The inventive subscriber unit initialization and synchronization method and apparatus uses a combination of an access burst format and a data transportation technique to efficiently use bandwidth when initializing and synchronizing subscriber units in a time-synchronized communication system. Advantageously, the present invention provides a mechanism for a base station to receive multiple access bursts from multiple subscriber units in a single contiguous time period. In the preferred embodiment of the present invention, bandwidth is efficiently utilized by searching for multiple initial access bursts from multiple mobile stations during a single time period known as a new access opportunity. The preferred embodiment of the present invention initializes and synchronizes subscriber units in a “contention-based” manner.
1. An apparatus, comprising:
a base station;
a media access control (MAC) element included in the base station and executed by a processor of the base station and configured to:
provide a contiguous new access opportunity time period on a frequency channel; and
provide one or more reserved time periods, different from the contiguous time period, for transmission to and from terminal stations on the frequency channel; and
an antenna coupled to the base station and configured to receive uplink communications from terminal stations,
wherein the contiguous new access opportunity time period has a duration of m+g+k, where m is an access burst duration, g is a maximum round-trip delay duration, and k is a time period greater than or equal to zero, wherein m, g, and k are real numbers, and
wherein if k is greater than zero, the antenna receives the uplink communications from terminal stations that randomize their transmission send time to reduce probability of collisions during the contiguous new access opportunity time period.
2. The apparatus of claim 1 wherein the antenna is further configured to:
receive a first registration message from a first unregistered terminal station during a first portion of the contiguous new access opportunity time period; and
receive a second registration message from a second unregistered terminal station during a second portion of the contiguous new access opportunity time period.
3. The apparatus of claim 2 wherein the MAC element is further configured to:
detect a collision of the first registration message and the second registration message, and
reject the first and second registration messages that have collided.
4. The apparatus of claim 1 wherein the MAC element is configured to provide the contiguous new access opportunity time period in an uplink bandwidth map of the frequency channel.
5. A method, comprising:
mapping, by a base station, onto an uplink map of a frequency channel:
a contiguous new access opportunity time period; and
one or more reserved time periods, different from the contiguous new access opportunity time period, for transmission to and from terminal stations;
wherein the contiguous new access opportunity time period has a duration of m+g+k, where m is an access burst duration, g is a maximum round-trip delay duration, and k is a time period greater than or equal to zero, wherein m, g, and k are real numbers, and
receiving, by said base station and if k is greater than zero, uplink communications from terminal stations that randomize their transmission send time to reduce probability of collisions during the contiguous new access opportunity time period.
6. The method of claim 5 , further comprising:
receiving, by the base station, a first registration message from a first unregistered terminal station beginning on a first time slot of the contiguous new access opportunity time period; and
receiving, by the base station, a second registration message from a second unregistered terminal station beginning on a second time slot of the contiguous new access opportunity time period.
7. The method of claim 6 , further comprising:
detecting, by the base station, a collision of the first registration message and the second registration message; and
rejecting, by the base station, the first and second registration messages that have collided.
8. The method of claim 5 , further comprising mapping, by the base station, a bandwidth request time period onto the uplink map of the frequency channel.
9. The method of claim 8 , further comprising:
receiving, by the base station from a first registered terminal station, a first bandwidth request beginning on a first time frame of the bandwidth request time period; and
receiving, by the base station from a second registered terminal station, a second bandwidth request beginning on a second time frame of the bandwidth request time period.
10. An article of manufacture, comprising:
a non-transitory computer-readable medium having processor-executable instructions stored thereon that are executable by a processor of a base station to:
map onto an uplink map of a frequency channel:
a contiguous new access opportunity time period; and
one or more reserved time periods, different from the contiguous new access opportunity time period, for transmission to and from terminal stations;
wherein the contiguous new access opportunity time period has a duration of m+g+k, where m is an access burst duration, g is a maximum round-trip delay duration, and k is a time period greater than or equal to zero, wherein m, g, and k are real numbers, and
receive, if k is greater than zero, uplink communications from terminal stations that randomize their transmission send time to reduce probability of collisions during the contiguous new access opportunity time period.
11. The article of manufacture of claim 10 wherein:
a first registration message is received by said base station from a first unregistered terminal station beginning on a first time slot of the contiguous new access opportunity time period,
a second registration message is received by said base station from a second unregistered terminal station beginning on a second time slot of the contiguous new access opportunity time period.
12. The article of manufacture of claim 11 wherein the non-transitory computer readable medium further includes instructions stored thereon that are executable by said processor to, if said base station detects a collision of the first registration message and the second registration message, cause said base station to reject the first and second registration messages that have collided.
13. The article of manufacture of claim 11 wherein the non-transitory computer readable medium further includes instructions stored thereon that are executable by said processor to map a bandwidth request time period onto the uplink map of the frequency channel.
14. The article of manufacture of claim 13 wherein the non-transitory computer readable medium further includes instructions stored thereon that are executable by said processor to:
process a first bandwidth request, received by the base station from a first registered terminal station, beginning on a first time frame of the bandwidth request time period; and
process a second bandwidth request, received by the base station from a second registered terminal station, beginning on a second time frame of the bandwidth request time period.