Apparatus and method for enhancing transfer rate using a direct link protocol (DLP) and multiple channels in a wireless local area network (LAN) using a distributed coordination function (DCF)

• US 20040264504A1
• Filed: 05/21/2004
• Published: 12/30/2004
• Est. Priority Date: 06/24/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jin, Ho
• Granted Patent: US 7,450,550 B2
• Time in Patent Office: Days
• US Class Current: 370/469
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 80/02 Data link layer protocols
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

An apparatus and a method for presenting a novel format of a media access control (MAC) frame that enables the use of a direct link protocol (DLP) and multiple channels, thereby reducing contention among stations, and enhancing a transfer rate by using the MAC frame format in infrastructure-based wireless communications. A DLP station of the present invention includes a channel-switching module for switching a channel by writing a new channel number in a DLP request frame; a mode-switching module for switching a DLP mode by writing a new mode number in the DLP request frame; and a MAC frame-generating module for generating various MAC frames including the DLP request frame.

Claims

1. A direct link protocol (DLP) station, comprising:

a channel-switching module for switching a channel by writing a new channel number in a DLP request frame;

a mode-switching module for switching a DLP mode by writing a new mode number in the DLP request frame; and

a medic access control (MAC) frame-generating module for generating various MAC frames including the DLP request frame.

2. The DLP station as claimed in claim 1, further comprising a MAC frame-transmitting/receiving module for transmitting the various frames generated by the MAC frame-generating module and receiving frames from one of other stations and an access point.

3. The DLP station as claimed in claim 2, wherein the MAC frame-generating module comprises:

a DLP request frame-generating module for generating the DLP request frame;

a DLP response frame-generating module for generating a DLP response frame in response to the DLP request frame; and

a MAC data frame-generating module for generating a MAC frame containing data to be sent to said other stations.

4. The DLP station as claimed in claim 3, wherein the MAC frame-generating module further comprises:

a DLP start frame-generating module for generating a DLP start frame which informs said other stations that a DLP has started, thereby causing another channel to be used depending on a channel mode; and

a DLP end frame-generating module for generating a DLP end frame which informs said other stations that the DLP is intended to be terminated.

5. An access point, comprising:

a channel list-managing module for managing and distributing a list of available channels through periodical analysis of channel conditions;

a channel number-writing module for checking whether there is an available DLP channel from the channel list and writing an available channel in a DLP request frame; and

a point coordinator module for performing buffering and management of a frame that is required to be sent to sleeping stations.

6. The access point as claimed in claim 5, further comprising a MAC frame-transmitting/receiving module for forwarding one of a received DLP request frame and a DLP response frame to other stations.

7. A wireless network system for enhancing throughput using a DLP and multiple channels, comprising:

a plurality of DLP stations and an access point,

wherein each of the plurality of DLP stations comprises;

a channel-switching module for switching a channel by writing a new channel number in a DLP request frame;

a mode-switching module for switching a DLP mode by writing a new mode number in the DLP request frame; and

a MAC frame-generating module for generating various MAC frames including the DLP request frame.

8. The wireless network system as claimed in claim 7, wherein each DLP station further comprises a MAC frame-transmitting/receiving module for transmitting various frames generated by the MAC frame-generating module and receiving frames from one of other stations and the access point.

9. The wireless network system as claimed in claim 8, wherein the MAC frame-generating module comprises:

a DLP request frame-generating module for generating the DLP request frame;

a DLP response frame-generating module for generating a DLP response frame in response to the DLP request frame; and

a MAC data frame-generating module for generating a MAC frame containing data to be sent to at least one of the DLP stations.

10. The wireless network system as claimed in claim 9, wherein the MAC frame-generating module further comprises:

a DLP start frame-generating module for generating a DLP start frame which informs the DLP stations that the DLP has started, thereby causing another channel to be used depending on a channel mode; and

a DLP end frame-generating module for generating a DLP end frame which informs the DLP stations that the DLP is intended to be terminated.

11. The wireless network system as claimed in claim 7, wherein the access point comprises:

a channel list-managing module for managing and distributing a list of available channels through periodical analysis of channel conditions;

a channel number-writing module for checking whether there is an available DLP channel from the channel list and writing an available channel in the DLP request frame; and

a point coordinator module for performing buffering and management of a frame that is required to be sent to sleeping stations.

12. The wireless network system as claimed in claim 11, wherein the access point further comprises a MAC frame-transmitting/receiving module for forwarding one of a received DLP request frame and a DLP response frame to other stations.

13. A method of enhancing throughput using a direct link protocol (DLP) and multiple channels, comprising:

(a) performing an improved 4-handshake process, and

(b) performing a mode corresponding to a DLP channel mode and a channel number that have been determined through the 4-handshake process,

wherein the step (a) comprises the steps of;

transmitting, by a sending station, a DLP request frame to an access point (AP);

writing, by the AP, an available channel number in the DLP request frame;

forwarding, by the AP, the DLP request frame to a receiving station;

transmitting, by the receiving station, a DLP response frame to the AP; and

forwarding, by the AP, the DLP response frame to the sending station.

14. The method as claimed in claim 13, wherein if the DLP channel mode is mode 1, the step (b) comprises the steps of:

(b-1) causing all stations to contend with one another for a channel; and

(b-2) transmitting data to the receiving station by the sending station that has won the channel contention.

15. The method as claimed in claim 13, wherein if the DLP mode is mode 2, the step (b) comprises the steps of:

(b-1) causing all stations to contend with one another for a channel;

(b-2) determining whether a DLP station has won the channel contention;

(b-3) determining whether the receiving station is a second DLP station if it is determined that the DLP station has won the channel contention; and

(b-4) performing a transmitting/receiving process of relevant data based on the results of the determination in steps (b-2) and (b-3).

16. The method as claimed in claim 15, wherein if it is determined in step (b-2) that the DLP station has lost the channel contention, step (b-4) comprises the steps of:

(i) transmitting data to the receiving station by the sending station that has won the channel contention; and

(ii) transmitting/receiving, by DLP stations, the data to/from one another using a DLP channel during a period of the data transmission/reception.

17. The method as claimed in claim 16, wherein step (b-4) further comprises, between steps (i) and (ii), the steps of:

transmitting a request to send (RTS) frame to the receiving station by the sending station that has won the channel contention;

setting up, by the remaining stations, their network allocation vector (NAV) values; and

transmitting a clear to send (CTS) frame by the receiving station, and

wherein step (b-4) further comprises, after step (ii), the step of transmitting an acknowledgement (ACK) frame by the receiving station.

18. The method as claimed in claim 15, wherein if it is determined in steps (b-2) and (b-3) that the DLP station has won the channel contention and the receiving station is the DLP station, step (b-4) comprises the steps of:

(i) broadcasting a DLP start frame;

(ii) setting up DLP network allocation vectors (NAVs) by remaining stations;

(iii) transmitting/receiving, by DLP stations, the data using a DLP channel; and

(iv) transmitting/receiving, by the remaining stations, the data during a period of the data transmission/reception.

19. The method as claimed in claim 15, wherein if it is determined in steps (b-2) and (b-3) that the DLP station has won the channel contention and the receiving station is not a DLP station, step (b-4) comprises the steps of:

(i) causing remaining stations to contend with one another for a channel; and

(ii) transmitting the relevant data to the receiving station by the sending station that has won the channel contention.

20. The method as claimed in claim 19, wherein step (b-4) further comprises, between steps (i) and (ii), the steps of:

transmitting a request to send (RTS) frame to the receiving station by the sending station that has won the channel contention;

setting up, by remaining stations, network allocation vector (NAV) values of the remaining stations; and

transmitting a clear to send (CTS) frame, by the receiving station, and

wherein step (b-4) further comprises, after step (ii), the step of transmitting an acknowledgement (ACK) frame, by the receiving station.

21. The method as claimed in claim 13, wherein if the DLP channel mode is mode 3, the step (b) comprises the steps of:

broadcasting a DLP start frame by a DLP sending station;

transmitting, by the DLP sending station, data to a DLP receiving station using a DLP channel during a period indicated in the DLP request frame;

transmitting/receiving, by the remaining stations, data to/from one another during the period; and

broadcasting, by the DLP sending station, a DLP end frame after the period.

22. The method as claimed in claim 21, wherein the step of transmitting/receiving, by the remaining stations, the data to/from one another comprises the steps of:

(i) causing remaining stations to contend with one another for a channel; and

(ii) transmitting the data to a second receiving station by a second sending station that has won the channel contention.

23. The method as claimed in claim 22, wherein the step of transmitting/receiving, by the remaining stations, the data to/from one another further comprises, between steps (i) and (ii), the steps of:

transmitting a request to send (RTS) frame to the second receiving station by the second sending station that has won the channel contention;

setting up, by the remaining stations, their network allocation vector (NAV) values; and

transmitting a clear to send (CTS) frame by the second receiving station, wherein the step of transmitting/receiving, by the remaining stations, the data to/from one another further comprises, after step (ii), the step of transmitting an acknowledgement (ACK) frame by the second receiving station.

24. A wireless network communication method using an access point in an infrastructure mode, comprising the steps of:

causing predetermined stations to contend with one another for a channel in a distributed coordination function (DCF) period;

allocating one available channel in a predetermined channel list to support the direct link protocol (DLP) communications if a station that has won the contention is a station that requires DLP communications; and

causing one of said predetermined stations except DLP stations to which the DLP channel is allocated, to contend with one another through a primary channel.

25. A wireless network communication method using an access point in an infrastructure mode, comprising the steps of:

causing predetermined stations to contend with one another for a channel in a distributed coordination function (DCF) period;

allocating one available channel in a predetermined channel list to support the DLP communications if a station that has won the contention is a station that requires DLP communications;

setting up a network allocation vector (NAV) value that is a communication time of DLP stations to which the DLP channel is allocated; and

causing the DLP channel and the predetermined stations to contend with one another through a primary channel after the time corresponding to the NAV value has passed.

26. A wireless network communication method using an access point in an infrastructure mode, comprising the steps of:

allocating one available channel in a predetermined channel list between stations that require direct link protocol (DLP) communications in order to support the DLP communications;

causing other stations, except DLP stations to which the DLP channel is allocated, to contend with one another through a primary channel;

informing said other stations, except the stations to which the DLP channel is allocated, of the end of the DLP communications if the communications between the stations to which the DLP channel is allocated are completed; and

causing the stations and predetermined stations to again contend with one another through a primary channel after the end of the DLP communications is informed.