Multiple Access Digital Communicating Method In Ultra-Wideband Radio Access Networks

• US 20080165746A1
• Filed: 03/28/2006
• Published: 07/10/2008
• Est. Priority Date: 03/28/2005
• Status: Active Grant

• Current Assignee: Pantech Corporation (Ideahub, Inc.)
• Original Assignee: Pantech Corporation (Ideahub, Inc.)
• Inventors: Hong, Young Jun, Jung, Bang Chul, Hwang, Ho Young, Chong, Jo Woon, Sung, Dan Keun, Jung, Chang Yong
• Granted Patent: US 8,588,190 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: H04B 7/2671 Arrangements for Wireless Time-Division Multiple Access [TDMA] System Synchronisation
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A multiple access digital communication method in ultra-wideband (UWB) radio access network is provided. More specifically, a multiple access technique in UWB communication channels is provided where UWB communication channels can be more efficiently used and collisions between multiple access user nodes can be more effectively avoided when the channels have a great multiple path fading. The digital communication method for use in an uplink in a UWB communication system includes the steps of: receiving data symbols from respective nodes, in which the data symbols are transmitted according to respective orthogonal time hopping patterns; checking whether there is a collision of the orthogonal time hopping patterns; and decoding the data symbols depending on whether data symbols of nodes involved in the collision of the orthogonal time hopping patterns are the same.

Claims

1. A digital communication method in an uplink of a UWB communication system, the method comprising:

synchronizing signals from respective user nodes with a management node; and

hopping available time slots for communication, according to orthogonal time hopping patterns assigned by the management node.

2. The method of claim 1, wherein the synchronization step comprises:

calculating time difference between the generation of a synchronization signal at the management node and the arrival of the synchronization signal at the user node; and

adjusting data transmission time to the management node according to the time difference.

3. A digital communication method in an uplink of a UWB communication system, the method comprising:

summing energies of received signals at time slots which are assigned to the respective user nodes through orthogonal time hopping patterns;

comparing the summed energy with a predetermined critical value; and

when the summed energy is greater than the critical value, judging that the user node has transmitted data.

4. A digital communication method in an uplink of a UWB communication system, comprising the steps of:

classifying user nodes into at least two groups; and

setting active periods by groups in a manner that the active periods are not overlapped with each other.

5. A digital communication method, comprising the steps of:

allowing user nodes to attempt multiple accesses by a scheduling based orthogonal time division method according to data transmission rates of services requested by the respective user nodes;

allowing user nodes to attempt multiple accesses by an orthogonal time hopping method using orthogonal time hopping patterns; and

classifying the user nodes into at least one group, and attempting communication by groups in a mixed mode of the orthogonal time division method and the orthogonal time hopping method.

6. The method of claim 5, wherein a power saving period is assigned in consideration of battery power consumption of the respective user nodes, and the mixed mode of the orthogonal time hopping method and the orthogonal time division method is used in an active period which is not the power saving period.

7. The method of claim 5, wherein the user nodes requesting high-speed data services accommodate a scheduling based multiple access, while the user nodes requesting mid/low speed data services accommodate the orthogonal time hopping method.

8. The method of claim 5, wherein reciprocal conversion of the multiple access methods is possible during communication.

9. The method of claim 5 is characterized by using one of the following schemes:

assigning time resources flexibly without distinguishing between uplink and downlink periods;

distinguishing between uplink and downlink periods, scheduling and mapping uplink and downlink data of a user node in orthogonal time division access uplink and downlink periods, and hopping time resources in orthogonal time hopping access uplink and downlink periods for communication; and

serving the uplink and downlink data by users in the orthogonal time division access period and thereby, reducing battery power consumption of the respective user nodes.

10. The method of claim 5, wherein the user nodes are classified into at least one group, and the orthogonal time hopping access method is used for the respective groups while the orthogonal time division method is used for the entire group.

11. The method of claim 5, wherein the classification of the user nodes into at least one group is determined by one of the following conditions:

data transmission rates requested by users;

distances between the respective user nodes and the management node;

received SINR values in the respective user nodes or the management node; and

user node ID numbers.

12. The method of claim 5, wherein after the user nodes are classified into at least one group, the user node groups are reclassified periodically or if necessary.

13. The method of claim 12 uses one of the following methods:

reclassifying user node groups per frame;

reclassifying user nodes groups in ‘

n’

frame unit (n>

1); and

reclassifying user node groups every time a user node joins with the management node through a contention access period for communication setup and communication initiation.

14. The method of claim 5, wherein time hopping patterns in the orthogonal time hopping multiple access method are managed by one of the following methods:

generating a time hopping pattern per frame by using an intrinsic ID assigned to each frame and an intrinsic identifier assigned to a user node;

assigning the time hopping patterns to users per frame by managing time hopping patterns in the orthogonal time hopping multiple access method in a table;

assigning the time hopping patterns in the orthogonal time hopping multiple access method in ‘

n’

frame unit (n>

1); and

assigning the time hopping patterns in the orthogonal time hopping multiple access method at a point when a user node joins with the management node through a contention access period for communication setup and communication initiation, and restoring the assigned time hopping patterns when service(s) of the user node ends.

15. The method of claim 5, wherein a node with information to be sent apart from specific time hopping patterns in the orthogonal time hopping multiple access method provides the management node with the data and a brief information about the presence of the data by using a specific time hopping pattern.

16. The method of claim 5, wherein the management node does not define a control signal channel regarding whether the respective user nodes have information to be sent for a downlink in the orthogonal time hopping multiple access method, but builds a bitmap of 1 bit information by users using the bitmap information in a beacon period and includes the bitmap in beacon information to inform the users.

17. The method of claim 5, wherein the management node does not define a control signal channel regarding whether the respective user nodes have information to be sent for a downlink in the orthogonal time division multiple access method, but builds a bitmap of 1 bit information by users using the bitmap information in a beacon period and includes the bitmap in beacon information to inform the users.

18. The method of claim 5, wherein a control signal channel indicating whether the respective nodes have information to be sent is not defined, but a received energy level of the management node is used to check whether data of the respective nodes exist in a frame.

19. The method of claim 5, wherein the management node does not define a control signal channel regarding whether the respective user nodes have information to be sent for a downlink in the orthogonal time hopping multiple access method, but includes only a user ID with information to be sent using the user ID in the beacon period to inform the users.

20. The method of claim 5, wherein the management node does not define a control signal channel regarding whether the respective user nodes have information to be sent for a downlink in the orthogonal time division multiple access method, but includes only a user ID with information to be sent using the user ID in the beacon period to inform the users.

21. A digital communication method in a contention access period in case that plural nodes set up communication concurrently with a communication network which has been in an initialized state, the method comprising the steps of:

dividing the entire contention access period into small time slots;

dividing the respective time slots into uplink mini-slots requesting communication setup and downlink mini-slots for giving an ACK thereto; and

in a node in need of communication setup, requesting the communication setup by randomly using one of the plural uplink mini-slots.

22. The method of claim 21, wherein when an uplink communication setup request of the node is transferred to a management node without causing an error or a collision, an ACK is sent immediately through a next downlink mini-slot.

23. A digital communication method in an uplink of a UWB communication system, comprising the steps of:

receiving data symbols from respective nodes, in which the data symbols are transmitted according to respective orthogonal time hopping patterns;

checking whether there is a collision of the orthogonal time hopping patterns; and

decoding the data symbols depending on whether data symbols of nodes involved in the collision of the orthogonal time hopping patterns are the same.

24. The method of claim 23, wherein, when data symbols of nodes involved in the collision of the orthogonal time hopping patterns are different from each other, the data symbols are regarded as not being received.

25. The method of claim 24, wherein the data symbols are regarded as not being received through decoding the data symbols with a neutralized value.

26. The method of claim 23, wherein, when data symbols of nodes involved in the collision of the orthogonal time hopping patterns are the same, the received data symbols are decoded as they are.

27. The method of claim 23, wherein, when a BPPM modulation method is used, whether the data symbols are the same is determined by using pulse energy values at respective pulse positions.

28. The method of claim 27, wherein whether the data symbols are the same is determined by pulse energy ratios at the respective pulse positions.

29. The method of claim 27, wherein whether the data symbols are the same is determined by absolute values of pulse energy at the respective pulse positions.

30. The method of claim 23, wherein, when a BPSK modulation method is used and when energy values of the received data symbol are greater than a predetermined threshold value, the data symbols of nodes involved in the collision of the orthogonal time hopping patterns are regarded to be the same.