Handover method for OFDM wireless communication system

• US 20060007888A1
• Filed: 06/20/2005
• Published: 01/12/2006
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Yonsei University
• Original Assignee: Samsung Electronics Co. Ltd., Yonsei University
• Inventors: Cho, Sung-Hyun, Lee, Sang-Hoon, Yun, Sang-Boh
• Granted Patent: US 7,729,313 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

An OFDM mobile communication system includes a system controller for dividing an OFDM symbol into a control channel and a data channel, multiplexing the control channel to control subchannels, and allocating the multiplexed control subchannels to base stations. The base stations simultaneously transmit control signals on the control allocated subchannels and data on the data channel. Mobile nodes receive an OFDM symbols with the multiplexed control channels for them and a data channel for selecting a base station according to information in the control subchannels. The mobile node simultaneously processes control subchannels received from two base stations using one physical layer module.

Claims

1. A resource allocation method in a multicarrier wireless communication system including a plurality of base stations transmitting data to mobile nodes through an entire system frequency band, the method comprising:

dividing the entire system frequency band into a control band and a data band; and

multiplexing the control band to control channels and allocating the multiplexed control channels to the base stations.

2. The method of claim 1, wherein the control band is multiplexed using Frequency Division Multiplexing (FDM).

3. The method of claim 1, wherein the control band is multiplexed using Code Division Multiplexing (CDM).

4. A data transmission method of a base station in a multicarrier wireless communication system including a plurality of base stations transmitting data to mobile nodes through an entire system frequency band, the method comprising:

dividing the entire system frequency band into a control band and a data band;

receiving one allocated control channel among control channels generated by multiplexing the control band; and

simultaneously transmitting a control signal and data by carrying the control signal on the allocated control channel and the data on the data band.

5. The method of claim 4, wherein the control band is multiplexed using FDM.

6. The method of claim 4, wherein the control band is multiplexed using CDM.

7. A data reception method of a mobile node in a multicarrier wireless communication system including a plurality of base stations transmitting data to mobile nodes through an entire system frequency band, the method comprising:

receiving signals of the entire system frequency band including a control band multiplexed to control channels for respective base stations and a data band shared by all of the base stations;

selecting a base station to which the mobile node is to be connected according to information included in the control channels for respective base stations of the control band; and

receiving data from the selected base station.

8. The method of claim 7, wherein the control band is multiplexed using FDM.

9. The method of claim 7, wherein the control band is multiplexed using CDM.

10. A handover method in a multicarrier wireless communication system including a plurality of base stations transmitting data to mobile nodes through an entire system frequency band, the method comprising the steps of:

receiving signals of the entire system frequency band including a control band multiplexed to control channels for respective base stations and a data band shared by all of the base stations;

simultaneously processing the control channels included in the control band;

selecting a base station according to the control channel process results; and

receiving data from the selected base station via the data channel.

11. The method of claim 10, wherein the control channels include pilot signals, respectively.

12. The method of claim 11, wherein the step of selecting a base station comprises:

measuring intensity of the pilot signals; and

selecting a base station with the highest intensity pilot signal.

13. The method of claim 12, wherein the step of selecting a base station comprises:

comparing intensity of the pilot signals from the base stations with a predetermined threshold;

registering the base stations if the intensity is greater than the predetermined threshold, as handover candidate base stations;

determining one of the handover candidate base stations as a handover-target base station if intensity of a pilot signal from a currently connected base station is close to the predetermined threshold;

sending a handover initialization request to the currently connected base station and the handover-target base station using a handover decision message; and

receiving a duplicate of data transmitted from the currently connected base station and preparing to transmit the duplicate to a mobile node in the handover-target base station if the handover decision message is received.

14. A resource allocation method in an OFDM wireless communication system, the method comprising:

dividing an OFDM symbol duration into a control channel and a data channel;

multiplexing the control channel to a plurality of control subchannels; and

allocating the multiplexed control subchannels to base stations.

15. The method of claim 14, wherein the control channel is multiplexed using FDM.

16. The method of claim 14, wherein the control channel is multiplexed using CDM.

17. A data transmission method of a base station in an OFDM wireless communication system, the method comprising:

dividing an OFDM symbol duration into a control channel and a data channel;

receiving one allocated control subchannel among control subchannels generated by multiplexing the control band; and

simultaneously transmitting a control signal and data by carrying the control signal on the allocated control subchannel and the data on the data channel.

18. The method of claim 17, wherein the control channel is multiplexed using FDM.

19. The method of claim 17, wherein the control channel is multiplexed using CDM.

20. A data reception method of a mobile node in an OFDM wireless communication system, the method comprising:

receiving an OFDM symbol including a control channel multiplexed to control subchannels for respective base stations and a data channel shared by all of the base stations;

selecting a base station to which the mobile node is to be connected according to information included in the control subchannels for respective base stations of the control channel; and

receiving data from the selected base station.

21. The method of claim 20, wherein the control channel is multiplexed using FDM.

22. The method of claim 20, wherein the control channel is multiplexed using CDM.

23. A mobile node in a multicarrier wireless communication system including a plurality of base stations transmitting data to mobile nodes through an entire system frequency band, the mobile node comprising:

a synchronization module for receiving signals of the entire system frequency band including a control band multiplexed to control channels for respective base stations and a data band shared by all of the base stations and performing timing synchronization on the received signals;

a demodulation module for demodulating the signals synchronized by the synchronization module;

a detection module for detecting the control channels for respective base stations from the signals demodulated by the demodulation module;

a selection module for selecting a base station according to the control channels for respective base stations detected by the detection module; and

a decoding module for restoring data received from the base station selected by the selection module via the data channel.

24. The mobile node of claim 23, wherein the control band is multiplexed using FDM.

25. The mobile node of claim 23, wherein the control band is multiplexed using CDM.

26. The mobile node of claim 23, wherein the demodulation module is a fast Fourier transformer.

31. The mobile communication system of claim 23, wherein the demodulation module simultaneously demonstrates the signals synchronized by the synchronization module.

27. An OFDM mobile communication system comprising:

a system controller for dividing an OFDM symbol into a control channel and a data channel, multiplexing the control channel to a plurality of control subchannels, and allocating the multiplexed control subchannels to base stations;

a plurality of base stations for receiving allocated control subchannels and simultaneously transmitting their own control signals and data by carrying their own control signals on the control subchannels and the data on the data channel; and

a plurality of mobile nodes for receiving an OFDM symbol including a control channel multiplexed to control channels for respective base stations and a data channel shared by all of the base stations and for selecting a base station to which they are to be connected according to information included in the control subchannels.

28. The mobile communication system of claim 27, wherein each base station comprises an inverse fast Fourier transformer for generating an OFDM symbol by modulating the control signal and the data.

29. The mobile communication system of claim 28, wherein each mobile node includes a physical layer module for simultaneously processing OFDM symbols received from the base stations.

30. The mobile communication system of claim 29, wherein the physical layer module is a fast Fourier transformer.