Apparatus and method for controlling operational states of medium access control layer in a broadband wireless access communication system

• US 20050047429A1
• Filed: 08/30/2004
• Published: 03/03/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Koo, Chang-Hoi, Lee, Sung-Jin, Son, Yeong-Moon, Kim, So-Hyun, Kang, Hyun-Jeong, Son, Jung-Je
• Granted Patent: US 7,400,642 B2
• Time in Patent Office: Days
• US Class Current: 370/447
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 74/0841 with collision treatment
• CPC Class Codes: H04W 76/27 Transitions between radio resource control [RRC] states
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Disclosed is a method for controlling an operational state of a medium access control layer in a broadband wireless access communication system. The method includes the steps of performing an uplink access of a contention-based scheme to an access point using resources required to perform the uplink access according to the contention-based scheme when data to be transmitted in an access state is detected, and being allocated resources required to perform an uplink access of a contention-free scheme from the access point in a case of failing in the uplink access of the contention-based scheme; and performing a state transition from the access state into the traffic state in a case of having been allocated the resource required for the contention-free scheme, and performing the uplink access of the contention-free scheme to the access point using the allocated resource in the traffic state.

Claims

1. A method for controlling an operational state of a medium access control layer in a broadband wireless access communication system, the method comprising the steps of:

performing an uplink access of a contention-based scheme to an access point using resources required to perform the uplink access according to the contention-based scheme when data to be transmitted is detected in an access state;

receiving resources required to perform an uplink access of a contention-free scheme from the access point in a case of failing in the uplink access of the contention-based scheme; and

performing a state transition from the access state into a traffic state in a case of receiving the resources required to perform the uplink access of the contention-free scheme, and performing the uplink access of the contention-free scheme to the access point using the received resources in the traffic state.

2. The method as claimed in claim 1, further comprising a step of transmitting the data to the access point when the uplink access of the contention-free scheme is succeeded.

3. The method as claimed in claim 1, wherein the resources required to perform the uplink access of the contention-based scheme are determined according to QoS (Quality of Service) classes of the data.

4. The method as claimed in claim 1, wherein the resources required to perform the uplink access of the contention-free scheme is allocated when the data has a QoS (Quality of Service) class greater than or equal to a predetermined priority.

5. The method as claimed in claim 3, wherein, the resources required to perform the uplink access of the contention-based scheme includes codes classified according to the QoS classes, and the higher the priority of the QoS class, the more the codes are classified into the QoS class.

6. The method as claimed in claim 1, wherein the resources required to perform the uplink access of the contention-free scheme include time slots.

7. A method for controlling an operational state of a medium access control layer in a broadband wireless access communication system, the medium access control layer having a null state for performing an initial operation following a reset, an initialization state for acquiring synchronization with an access point and performing a network entry operation to the access point, a sleeping state for performing a wake-up operation by a control of the access point or when there is data to be transmitted to the access point, an access state for performing an uplink access of a contention-free scheme to the access point, and a traffic state for transmitting data to the access point or receiving data from the access point, the method comprising the steps of:

allocating codes by the access point for uplink access of a contention-based scheme and allocating codes by the access point for the uplink access of the contention-free scheme according to QoS (Quality of Service) classes;

selecting a first code by an access terminal, according to the QoS classes of data to be transmitted from among the allocated codes for the uplink access of the contention-based scheme, when the data to be transmitted through an uplink in the access state is generated, and performing an uplink access of the contention-based scheme to the access point using the first code;

allocating by the access point a second code, from among the codes for uplink access of the contention-free scheme, to the access terminal so that the access terminal can perform an uplink access of the contention-free scheme, when it fails to allocate the access terminal a resource for data transmission of the access terminal in response to the uplink access performed by the access terminal; and

performing by the access terminal a state transition from the access state into the traffic state when allocated the second code, and performing an uplink access of the contention-free scheme to the access point using the second code in the traffic state.

8. The method as claimed in claim 7, further comprising a step of transmitting the data to the access point when the uplink access of the contention-free scheme is succeeded after performing the uplink access of the contention-free scheme.

9. The method as claimed in claim 7, wherein the second code is allocated when the data has a QoS class is equal to or greater than a predetermined reference priority.

10. The method as claimed in claim 7, wherein the higher the priority of the QoS class, the more the codes are classified to the QoS class are.

11. A method for controlling an operational state of a medium access control layer in a broadband wireless access communication system, the method comprising of the steps of:

acquiring synchronization with an access point to which an access terminal belongs in a system detecting mode of an initialization state, performing a mode change from the system detecting mode into a network entry mode, and performing a network entry operation to the access point in the network entry mode;

entering a sleeping mode of a sleeping state from the network entry mode when there is no data to be transmitted to the access point or received from the access point, entering an access state from the network entry mode when there is data to be transmitted to the access point, and entering a traffic state from the network entry mode when there is data to be received from the access point, after performing the network entry operation;

entering an awake mode of the sleeping state when there is data to be transmitted to the access point or when a wake-up is requested from the access point in the sleeping state, and entering the access state from the awake mode when there is data to be transmitted to the access point; and

receiving predetermined information from the access point in the awake mode, and entering either the sleeping mode or the traffic state from the awake mode according to the predetermined information.

12. The method as claimed in claim 11, wherein, the step of performing the network entry operation to the access point comprises the steps of:

transmitting a network entry request message to the access point through an access channel corresponding to predetermined uplink access information; and

receiving a network entry response message from the access point in response to the network entry request message, the network entry response message including slot index information of a wake-up channel which the access terminal monitors to detect whether a wake-up request is generated from the access point in the sleeping mode.

13. The method as claimed in claim 12, further comprising a step of monitoring only the wake-up channel in the sleeping mode.

14. The method as claimed in claim 12, wherein a slot index of the wake-up channel, which the access terminal monitors, is determined as a particular value in the access point and is continuously maintained in the access point.

15. A method for controlling an operational state of a medium access control layer in a broadband wireless access communication system, the method comprising the steps of:

transmitting by an access point a pilot channel signal and a broadcast channel signal, the pilot cannel signal being used for synchronization acquisition with an access terminal, the broadcast channel signal including system information of the broadband wireless access communication system;

acquiring by the access terminal synchronization with the access point, to which the access terminal itself belongs, using the pilot channel signal in a system detecting mode of an initialization state, and entering a network entry mode;

receiving by the access terminal the broadcast channel signal and transmitting a network entry request message to the access point in the network entry mode;

transmitting by the access point a network entry response message to the access terminal in response to the network entry request message, the network entry response message including slot index information of a wake-up channel which the access terminal monitors in the sleeping mode of the sleeping state; and

receiving by the access terminal the network entry response message, and entering the sleeping mode when there is no data to be transmitted to the access point or received from the access point, thereby monitoring a wake-up indicator of the wake-up channel corresponding to the slot index information.

16. The method as claimed in claim 15, further comprising the steps of:

setting by the access point a wake-up indicator corresponding to the slot index information to ‘

on’ and

transmitting the wake-up channel signal, when there is data to be transmitted to the access point or when the system information is updated, after transmitting the network entry response message;

entering by the access terminal an awake mode of the sleeping state from the sleeping mode when the wake-up indicator of the wake-up channel corresponding to the slot index information is set to ‘

on’

;

transmitting by the access point the broadcast channel signal which includes paging information representing the updated system information or representing that there are data to be transmitted to the access terminal; and

receiving by the access terminal the broadcast channel signal, entering the sleeping mode after applying the updated system information when the broadcast channel signal includes the updated system information, and entering an traffic state when the broadcast channel signal includes the paging information.

17. The method as claimed in claim 15, further comprising the steps of:

setting by the access point a wake-up indicator corresponding to the slot index information to ‘

off’ and

transmitting the wake-up channel signal, when there is no data to be transmitted to the access terminal and when the system information is not updated, after transmitting the network entry response message; and

maintaining by the access terminal the sleeping mode when the wake-up indicator of the wake-up channel corresponding to the slot index information is set to ‘

off’

.

18. An apparatus for transmitting a wake-up channel in a broadband wireless access communication system, the apparatus comprising:

a symbol repeater for receiving wake-up indicators, a number of frames constructing a super frame of a wake-up channel, and a frame period, the wake-up indicators representing whether or not access terminals in a sleeping mode of a sleeping state wake up, the wake-up channel including the wake-up indicators, the frame period representing a period in which the wake-up indicators are transmitted in the super frame, and for repeating a symbol of the wake-up indicators according to a transmission format of the wake-up channel;

a wake-up channel information mapper for receiving slot index information according to a predetermined control and on/off setting information of the wake-up indicator, and for setting the wake-up indicators, which exists in slots corresponding to the slot index information, from among signals output from the symbol repeater, according to the on/off setting information; and

a controller for determining access terminals to which data or updated system information is transmitted when there is data to be transmitted or when the system information is updated, and for outputting slot index information and first setting information to the wake-up channel information mapper, the slot index information monitored by the determined access terminals, the first information representing that wake-up indicators corresponding to the slot index information have to be set to ‘

on’

.

19. The apparatus as claimed in claim 18, wherein the controller outputs second information, which represents that the wake-up indicators have to be set to ‘

off’

, to the wake-up channel information mapper, when there is no data to be transmitted and when the system information is not updated.

20. The apparatus as claimed in claim 19, further comprising a channel gain multiplier which multiplies a signal output from the wake-up channel information mapper by a predetermined channel gain, and outputs the resultant.

21. A method for transmitting a wake-up channel in a broadband wireless access communication system, the method comprising the steps of:

receiving wake-up indicators, a number of frames constructing a super frame of a wake-up channel, and a frame period, the wake-up indicators representing whether or not access terminals in a sleeping mode of a sleeping state wake up, the wake-up channel including the wake-up indicators, the frame period representing a period in which the wake-up indicators are transmitted in the super frame, and repeating a symbol of the wake-up indicators according to a transmission format of the wake-up channel;

determining access terminals to which data or updated system information is transmitted when there is the data to be transmitted or when the system information is updated, and determining slot index information which the determined access terminals monitor; and

setting wake-up indicators corresponding to the determined slot index information to ‘

on’

, and transmitting the wake-up channel signal.

22. The method as claimed in claim 21, further comprising a step of setting the wake-up indicators to ‘

off,’

when there is no data to be transmitted and when the system information is not updated, and transmitting the wake-up channel signal.

23. A method for controlling an operational state of a medium access control layer in a broadband wireless access communication system, the method comprising the steps of:

entering an active mode of a traffic state, when there is data to be received from an access point in one of an initialization state and in a sleeping state, or when an uplink bandwidth is allocated according to uplink access performance of a contention-based scheme in an access state;

entering a hold mode when data transmission to the access point or data reception from the access point is interrupted for a predetermined period of time during data transmission to the access point or data reception from the access point while in an active mode;

receiving a predetermined channel signal in the hold mode so as to monitor whether or not a wake-up request is generated from the access point, entering the active mode when a wake-up request is generated from the access point, and entering the fast access mode when data to be transmitted to the access point is generated in the hold mode; and

performing an uplink access of a contention-free scheme to the access point in the fast access mode using resources for the uplink access of the contention-free scheme, and entering the active mode when being allocated the uplink bandwidth as a result of the uplink access performance of the contention-free scheme.

24. The method as claimed in claim 23, further comprising the step of entering the fast access mode of the traffic state, when being allocated resources for the uplink access of the contention-free scheme during the uplink access of the contention-based scheme while in the access state.

25. The method as claimed in claim 23, wherein a resource for the uplink access of the contention-free scheme includes a code and a time slot, which are used when the uplink access of the contention-free scheme is performed in the fast access mode, which are different from a code and a time slot used when an uplink access of the contention-based scheme is performed.

26. The method as claimed in claim 23, further comprising the step of maintaining the active mode although data transmission or data reception is interrupted during a predetermined period of time, when a QoS (Quality of Service) class of data to be transmitted to the access point or received from the access point in the active mode is equal to or greater than a predetermined reference priority.

27. The method as claimed in claim 23, wherein the set channel includes a wake-up channel.

28. A method for controlling an operational state of a traffic state in a broadband wireless access communication system, the method comprising the steps of:

1) transmitting data to an access point or receiving data from an access point by an access terminal in an active mode;

2) requesting the access terminal to perform a mode change from the active mode into a hold mode by the access point, when the data transmission to the access terminal or data reception from the access terminal, which is in the active mode, is interrupted during a predetermined period of time;

3) entering the hold mode by the access terminal after transmitting a response to the access point in response to the mode change request of step

     2), receiving a set channel signal, which is monitored to determine if a wake-up request is generated from the access point, entering the active mode when a wake-up request is generated from the access point, and entering a fast access mode when data to be transmitted to the access point are generated in the hold mode;

4) requesting by the access terminal in the fast access mode that a mode of the access terminal is changed from the fast access mode into active mode using a resource for uplink access of a contention-free scheme; and

5) transmitting a response to the access terminal by the access point in response to a mode change request of step

     4), thereby causing the access terminal to perform a mode change from the fast access mode into the active mode and to transmit the data to the access point.

29. The method as claimed in claim 28, wherein step 2) comprises the steps of:

determining by the access point that a mode of the access terminal is changed from the active mode into the hold mode, when the data transmission to the access terminal or data reception from the access terminal, which is in the active mode, is interrupted during a predetermined period of time; and

determining by the access point a resource for uplink access of the contention-free scheme, which the access terminal uses in the fast access mode, after determining the mode change, and requesting the access terminal to perform a mode change from the active mode into the hold mode through transmission of a signal including the determined resource for uplink access of the contention-free scheme.

30. The method as claimed in claim 29, wherein in step 4) the access terminal requests that a mode of the access terminal has to be changed from the fast access mode into an active mode, using resources for an uplink access of the contention-free scheme which is received in the active mode before entering the hold mode.

31. The method as claimed in claim 30, wherein the resources for the uplink access of the contention-free scheme includes a code and a time slot used when uplink access of the contention-free scheme is performed in the fast access mode.

32. The method as claimed in claim 28 wherein the set channel includes a wake-up channel.

33. The method as claimed in claim 28, wherein a mode change request of step 2) is transmitted through a downlink traffic channel, the response to the mode change request of step 2) is transmitted through an uplink traffic channel, a mode change request of step 4) is transmitted through a fast access channel, and the response to the mode change request of step 4) is transmitted through a scheduling channel.

34. A method for controlling an operational state of a traffic state in a broadband wireless access communication system, the method comprising the steps of:

1) requesting by an access terminal an access point that a mode of the access terminal itself is changed from an active mode into a hold mode when data transmission or data reception is interrupted for a predetermined period of time during the data transmission/reception to/from the access point while in the active mode;

2) transmitting by the access point a response to a mode change request of step

     1) to the access terminal, thereby causing the access terminal to enter the hold mode;

3) requesting by the access point the access terminal to change a mode of the access terminal from the hold mode into the active mode when detecting that data to be transmitted to the access terminal being in the hold mode are generated; and

4) performing by the access terminal a mode change from the hold mode into the active mode according to a mode change request of step

     3), thereby receiving the data from access point.

35. The method as claimed in claim 34, further comprising step 5) of performing by the access terminal a mode change from the hold mode into the active mode according to the mode change request of step 3) and transmitting a response to the mode change request of step 3).

36. The method as claimed in claim 35, wherein in step 2), the access point detects a mode change request of step 1), determines a resource for uplink access of a contention-free scheme which the access terminal uses in the fast access mode, and transmits a response, which includes the determined resource for uplink access of the contention-free scheme, to the access terminal in response to the mode change request of step 1).

37. The method as claimed in claim 36 wherein, in step 5) the access terminal transmits a response to the mode change request of step 3) to the access point, using a resource for uplink access of the contention-free scheme received in the active mode before the access terminal enters the hold mode.

38. The method as claimed in claim 37, wherein the resource for uplink access of the contention-free scheme includes a code and a time slot used when uplink access of the contention-free scheme is performed in the fast access mode.

39. The method as claimed in claim 38, wherein, the mode change request of step 1) is transmitted through an uplink traffic channel, the response to the mode change request of step 1) is transmitted through a downlink traffic channel, the mode change request of step 3) is transmitted through a wake-up channel, and the response to the mode change request of step 3) is transmitted through a fast access channel.