Medium access method for contention and non-contention

• US 20060114878A1
• Filed: 11/04/2005
• Published: 06/01/2006
• Est. Priority Date: 11/26/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Uh, Rae-Jin, Na, Sung-Guk, Seo, Chang-Woo, Choe, Mi-Ra
• Granted Patent: US 8,259,655 B2
• Time in Patent Office: Days
• US Class Current: 370/346
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

In a medium access method for contention and non-contention, a poll number for stations, or wireless terminals for communication, is managed by a base station so as to guarantee smooth traffic and improved Quality of Service (QoS). A first group of stations is provided for the non-contention, and a second group of stations is provided for the contention. The method includes (a) preparing a contention-free access message attempting access of the first group, (b) detecting a transmission time of a contention access message attempting access of the second group, (c) embedding the contention-free access message in the contention access message so as to transmit the embedded message to at least one of the first and second groups, and (d) receiving the contention access message, in which the contention-free access message is embedded, at the at least one of the first and second groups, and endowing any one of the first and second groups with a priority to attempt access to a medium in turn. Thereby, a poll number control-based multi-polling distributed coordination function (MP-DCF) mechanism is shared with the commercial stations to which no MP-DCF module is provided, so that it is possible to solve a drawback in that all stations should have the MP-DCF module provided therein, as well as to constantly maintain throughput even though the number of stations is gradually increased.

Claims

1. A medium access method for contention and non-contention, wherein a first group has a plurality of stations for the non-contention and a second group has a plurality of stations for the contention, the medium access method comprising the steps of:

(a) preparing a contention-free access message attempting access of the first group;

(b) detecting a transmission time of a contention access message attempting access of the second group;

(c) embedding the contention-free access message in the contention access message so as to transmit the embedded message to at least one of the first and second groups during the transmission time of the contention access message; and

(d) receiving the contention access message with the contention-free access message embedded therein at said at least one of the first and second groups, and endowing any one of the first and second groups with a priority to attempt access to a medium in turn.

2. The medium access method as claimed in claim 1, wherein the contention-free access message has an access schedule, and is formed of a multi-polling message for causing the stations of the first group to attempt sequential access according to the access schedule.

3. The medium access method as claimed in claim 2, wherein the access schedule sets a backoff rank for getting access for each of the stations and has a backoff time value depending on the backoff rank.

4. The medium access method as claimed in claim 1, wherein the contention access message is formed of a beacon message for attempting contention access, and the beacon message secures a contention period, exclusive of a contention-free period, based on the contention-free access message.

5. The medium access method as claimed in claim 1, wherein, when the first group has the priority endowed in step (d), the first group gets access to the medium according to access scheduling within a contention-free period, and the second group has a network allocation vector set for the contention-free period so as to maintain a standby state and attempts the medium access within a contention period subsequent to the standby state.

6. The medium access method as claimed in claim 5, wherein the contention-free period includes a first period for sequentially uploading data of the stations of the first group to an access point, and a second period for sequentially downloading data corresponding to the uploaded data to each of the stations generating the uploaded data.

7. The medium access method as claimed in claim 1, further comprising, when the second group has the priority in the step (d), setting a network allocation vector for the first group so as to maintain a standby state for a contention period of the second group, and setting the network allocation vector for the second group so as to maintain the standby state for a contention-free period for attempting sequential medium access according to an access schedule after the standby state.

8. A medium access method for contention and non-contention between at least one of a first group and a second group, and an access point, wherein the first group has at least one station for getting access to a medium without contention, and the second group has at least one station for getting access to the medium through contention, the medium access method comprising the steps of:

(a) receiving a beacon message embedded with a multi-polling message at the first and second groups;

(b) setting a network allocation vector by means of the first and second groups themselves receiving the beacon message;

(c) removing the network allocation vector of the first group stored with a polling list in the first and second groups for which the network allocation vector is set;

(d) determining whether data to be transmitted from each of the stations of the first group removing the network allocation vector are present;

(e) uploading the data to the access point in turn according to an access schedule of the multi-polling message by means of the stations having the data;

(f) maintaining a standby state for a contention-free period by means of the stations of the second group themselves from which the network allocation vector is not removed;

(g) receiving a contention-free end signal after the contention-free period so as to remove the network allocation vector; and

(h) transmitting data to and receiving data from the access point in a contention mechanism by the stations of the second group removing the network allocation vector.

9. The medium access method as claimed in claim 8, further comprising, after the stations of the first group upload the data to the access point, downloading data of the access point, corresponding to the uploaded data, to each of the stations of the first group in turn.

10. The medium access method as claimed in claim 8, further comprising, when the data to be transmitted from at least one of the stations of the first group are not present, setting a minimum value of a random contention window as a value of a number of a poll to wait for the next beacon message.

11. The medium access method as claimed in claim 8, wherein step (f) includes:

determining whether at least one of the stations of the second group is on standby in order to acquire a transmission chance;

when said at least one of the stations of the second group is on standby, causing a value of a backoff number, to which a rank decided through the contention is being decreased, to be increased up to a current backoff number so as to maintain the standby state; and

when said at least one of the stations of the second group is not on standby, setting a minimum value of a random contention window as a value of a number of a poll so as to wait for the next beacon message.

12. A medium access method for contention and non-contention, comprising the steps of:

(a) providing a superframe in which any one of a contention-free period, wherein a first group having at least one station gets access to an access point without contention, and a contention period, wherein a second group having at least one station gets access to the access point without contention, is formed as a first half, and in which another of the contention-free period and the contention period is formed as a second half;

(b) uploading data to the access point in turn at each of the stations of the first group for a first period of the contention-free period; and

(c) downloading data, corresponding to the uploaded data, to each of the stations of the first group at the access point in turn for a second period of the contention-free period.

13. A medium access method for contention and non-contention, comprising the steps of:

(a) providing an access point and at least one station for the contention and non-contention to get access to a medium;

(b) transmitting a beacon message embedded with a multi-polling message;

(c) providing a contention-free period for uploading and downloading data between the access point and said at least one station getting access to the medium according to the multi-polling message of the beacon message; and

(d) providing a contention period for uploading and downloading the data through the contention between the access point and said at least one station getting access to the medium according to the multi-polling message of the beacon message.

14. The medium access method as claimed in claim 13, wherein step (c) comprises:

uploading the data to the access point in turn at all of the stations for a first period of the contention-free period; and

downloading the data, corresponding to the uploaded data, to each of the stations at the access point in turn for a second period of the contention-free period.

15. The medium access method as claimed in claim 13, wherein the multi-polling message includes an access schedule for getting access to the access point, the access schedule being allocated to each of the stations.