Method for accessing hybrid network, and gateway apparatus, wireless terminal and communication system thereof

• US 8,160,048 B2
• Filed: 10/18/2006
• Issued: 04/17/2012
• Est. Priority Date: 10/19/2005
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Du, Lei, Bai, Yong, Chen, Lan, Kayama, Hidetoshi
• Primary Examiner(s): Eng, George
• Assistant Examiner(s): SIVJI, NIZAR N
• Application Number:
  US11/583,651
• Publication Number:
  US 20070098009A1
• Time in Patent Office: 2,008 Days
• Field of Search: 370/338, 370/468, 370/351, 370/346, 370/445, 455/13.1, 455/426.1, 455/443, 375/316
• US Class Current: 370/346
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 48/14 using user query or user detection
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method for accessing a hybrid network including a wide area network and a distributed network, a gateway apparatus, a wireless terminal and a gateway communication system are disclosed for reducing the power consumption of the wireless terminal which is an access gateway. The method comprises: sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wide area network; transmitting by a wireless terminal a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and if the relay request signal from the wireless terminal is sensed in the relay request slot, establishing by the gateway apparatus a connection with the wireless terminal in a distributed network environment. As such, the gateway apparatus accesses the wireless distributed network only when the surrounding wireless terminals require data relay, without sensing signals on both networks simultaneously, in order to reduce the power consumption.

Claims

1. A method for accessing a hybrid network including a wireless wide area network and a wireless distributed network, comprising the steps of:

sensing by a gateway apparatus a relay request slot on a downlink common control channel of the wireless wide area network;

transmitting by a wireless terminal, a relay request signal requesting to relay a data packet to be transmitted, in the relay request slot on the downlink common control channel; and

establishing by the gateway apparatus a connection with the wireless terminal in the wireless distributed network, if the relay request signal from the wireless terminal is sensed in the relay request slot;

wherein establishing a connection with the wireless terminal comprises;

transmitting by the gateway apparatus a reply signal to the wireless terminal after receiving the relay request signal;

determining by the wireless terminal a gateway apparatus through which a relay operation is to be made by measuring channel conditions, and transmitting a selection signal containing an address of the gateway apparatus through which the relay operation is to be made; and

after receiving the selection signal, transmitting, by the gateway apparatus corresponding to the address in the selection signal, a permit signal for permitting the wireless terminal to transmit a data packet to be relayed to the wireless terminal;

wherein the wireless terminal compares conditions of channels indicated in the reply signal, and selects a gateway apparatus with the best condition of channel as the gateway apparatus through which the relay operation is to be made; and

the wireless terminal selects a gateway apparatus that needs the lowest transmission power for directly communicating therewith as the gateway apparatus through which the relay operation is to be made.

2. The method according to claim 1, further comprising the steps of:

transmitting by the wireless terminal a data packet to the gateway apparatus through the connection; and

relaying by the gateway apparatus the data packet received from the wireless terminal to the wireless wide area network.

3. The method according to claim 1, wherein the gateway apparatus performs data packet transmissions with multiple wireless terminals around in a polling manner.

4. The method according to claim 1, wherein if the wireless terminal receives no reply signal in a predetermined time, then a contention window is enlarged and a random period is backed-off;

and the relay request signal is retransmitted on a relay request slot detected after the back-off time period.

5. The method according to claim 1, wherein the wireless terminal selects a gateway apparatus with the highest signal to interference and noise ratio as the gateway apparatus through which the relay operation is to be made.

6. The method according to claim 1, wherein the wireless terminal selects the nearest gateway apparatus as the gateway apparatus though which the relay operation is to be made.

7. The method according to claim 1, wherein once the gateway apparatus detects that a power level on the relay request slot is larger than a noise power, it transmits the reply signal in the wireless distributed network environment.

8. The method according to claim 1, wherein once the gateway apparatus detects a high level on the relay request slot, it transmits the reply signal in the distributed network environment.

9. The method according to claim 1, wherein after successfully receiving the data packet to be relayed, the gateway apparatus transmits an acknowledgement signal to the wireless terminal.

10. The method according to claim 1, wherein the downlink common control channel is a broadcast channel.

11. A wireless terminal which performs communication through a relay of a gateway apparatus in a hybrid network including a wireless wide area network and a wireless distributed network, the wireless terminal comprising:

a distributed network transceiving unit for transmitting and receiving signals in the wireless distributed network;

a downlink common control channel transceiving unit for transmitting a relay request signal requesting to relay a data packet to be transmitted and receiving signals on a downlink common control channel of the wireless wide area network;

a detection unit for detecting the signals received by the downlink common control channel transceiving unit on the downlink common control channel, and detecting the type of current slot on the downlink common control channel; and

an access determination unit for receiving information from the detection unit and determining a network to be accessed currently;

wherein the downlink network transceiving unit transmits the relay request signal in a relay request slot on the downlink common control channel detected by the detection unit;

and further wherein, when the access determination unit instructs to access the wireless distributed network, the transmission control unit begins clocking, and signal is received by the distributed network transceiving unit within a reception threshold time;

when the reception threshold time is reached, if a reply signal is correctly received, the distributed network transceiving unit is instructed to transmit a selection signal containing an address of an gateway apparatus through which the relay operation is to be made;

the transmission control unit compares conditions of channels indicated in the reply signal, and selects a gateway apparatus with the best condition of channel as the gateway apparatus through which the relay operation is to be made; and

the transmission control unit selects a gateway apparatus which needs the lowest transmission power for directly communicating with the wireless terminal as the gateway apparatus through which the relay operation is to be made.

12. The wireless terminal according to claim 11, further comprising:

a transmission storage unit for storing packets to be transmitted;

a transmission control unit for receiving results from the access determination unit and the detection unit, controlling transmission and reception of signals the wireless distributed network, and clocking; and

a delay unit for receiving an instruction from the transmission control unit and delaying.

13. The wireless terminal according to claim 11, wherein

when a packet to be transmitted is stored in the transmission control unit of the wireless terminal, the access determination unit instructs to access the downlink common control channel, and the relay request signal is transmitted on the relay request slot detected by the detection unit through the downlink common control channel transceiving unit.

14. The wireless terminal according to claim 13, wherein after the transmission of the relay request signal is completed, the access determination unit instructs to access the wireless distributed network and enables the transmission control unit.

15. The wireless terminal according to claim 11, wherein if no packet is received, then the delay unit is enabled for backing-off a random period.

16. The wireless terminal according to claim 11, wherein when the distributed network transceiving unit receives a permit signal for permitting a transmission of a data packet to be relayed, the data packet is transmitted;

and when the distributed network transceiving unit successfully receives an acknowledgement signal, the access determination unit is instructed to stop accessing the wireless distributed network.

17. The wireless terminal according to claim 11, wherein the transmission control unit selects a gateway apparatus with the highest signal to interference and noise ratio as the gateway apparatus through which the relay operation is to be made.

18. The wireless terminal according to claim 11, wherein the transmission control unit selects the nearest gateway apparatus as the gateway apparatus through which the relay operation is to be made.

19. The wireless terminal according to claim 13, wherein the downlink common control channel is a broadcast channel.

20. The wireless terminal according to claim 11, wherein the distributed network transceiving unit comprises:

a distributed network transmission unit for transmitting signals in the wireless distributed network; and

a distributed network reception unit for receiving signals from the wireless distributed network.

21. The wireless terminal according to claim 11, wherein the downlink common control channel transceiving unit comprises:

a downlink common control channel transmission unit for transmitting a relay request signal on the downlink common control channel of the wireless wide area network; and

a downlink common control channel reception unit for receiving signals on the downlink common control channel of the wireless wide area network.

22. A communication system including the wireless terminal according to claim 11.