# US 2008/0186945 A1 · Wireless lan system and transmission method of data thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0186945 A1 - Document ID: US20080186945A1 - Status: Published application - Kind: A1 - Application number: 11/833,366 - Filed: 2007-08-03 - Published: 2008-08-07 - Earliest claimed: 2007-02-06 - Assignees: LG Eletronics Inc. - Inventors: Tae Hee Ahn - Web page: https://patentgrep.com/patent/US20080186945A1 ## CPC - H04L 1/16: in which the return channel carries supervisory signals, e.g. repetition request signals - H04L 1/1887: {Scheduling and prioritising arrangements} - H04W 72/535: {based on resource usage policies} - H04W 72/566: of the information or information source or recipient - H04W 84/12: WLAN [Wireless Local Area Networks] - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present invention relates to a frame transmission scheduling method of a wireless communication considering frame transmission delay time information. The present invention provides a wireless communication system, which comprises a transmitting station for storing a transmission time in a transmission frame, calculating a delay time using the transmission time when retransmission of the transmission frame is requested, and scheduling the transmission of the transmission frame using the delay time; and a receiving station for transmitting a response frame (ACK frame) to the transmitting station when receiving the transmission frame. According to the present invention so configured, since transmission delay time information of a frame is considered when scheduling a sequence of frame transmission, there is an advantage in that waste of wireless resources due to retransmission delay of frames can be prevented. ## Claims ### Claim 1 A wireless communication system, comprising: a transmitting station for storing a transmission time in a transmission frame, calculating a delay time using the transmission time when retransmission of the transmission frame is requested, and scheduling the transmission of the transmission frame using the delay time; and a receiving station for transmitting a response frame (ACK frame) to the transmitting station when receiving the transmission frame. ### Claim 2 (depends on 1) The system as claimed in claim 1, wherein the transmission time is stored in a delay parameter area provided in a MAC header of the transmission frame. ### Claim 3 (depends on 2) The system as claimed in claim 2, wherein the transmission frame is scheduled by dividing a predetermined range of time period into a plurality of groups, putting an adjustment value to each group, changing the user priority according to the adjustment value of a group corresponding to the delay time, and performing the transmission frame scheduling based on the changed user priority. ### Claim 4 (depends on 3) The system as claimed in claim 3, wherein the user priority is set to zero if the changed user priority is smaller than zero; and the user priority is set to seven if the changed user priority is greater than seven. ### Claim 5 (depends on 2) The system as claimed in claim 2, wherein the transmission frame is scheduled by setting a delay grade based on the delay time and storing the delay grade, and primarily determining an access category (AC) according to the user priority and adjusting the AC in consideration of the delay grade to determine a final AC to which the transmission frame belongs. ### Claim 6 (depends on 2) The system as claimed in claim 2, wherein the transmission frame is scheduled by determining whether the delay time exceeds a predetermined time period, and assigning the transmission frame to a transmission queue corresponding to a highest user priority to preferentially transmit the transmission frame if the delay time exceeds the predetermined time period. ### Claim 7 (depends on 2) The system as claimed in claim 2, wherein the transmission frame is scheduled by determining whether the delay time exceeds a predetermined time period, and assigning the transmission frame to a transmission queue with a user priority one level higher than that of a transmission queue corresponding to the user priority of the transmission frame to transmit the transmission frame, if the delay time exceeds the predetermined time period. ### Claim 8 (depends on 1) The system as claimed in claim 1, wherein the transmitting station is an access point, and the receiving station is a terminal device. ### Claim 9 (depends on 1) The system as claimed in claim 1, wherein the transmission frame is a QoS data frame. ### Claim 10 (depends on 1) The system as claimed in claim 1, wherein the wireless communication is in ad-hoe mode, and the transmitting and receiving stations are terminal devices. ### Claim 11 A wireless communication system, comprising: a transmitting station for storing a transmission time in a transmission frame, the transmitting station including a virtual collision handler for selecting a frame to be transmitted using a delay time calculated from the transmission time when a collision occurs between ACs; and a receiving station for transmitting a response frame (ACK frame) to the transmitting station when receiving the transmission frame. ### Claim 12 (depends on 11) The system as claimed in claim 11, wherein the virtual collision handler divides a predetermined range of time period into a plurality of groups, puts an adjustment value to each group, changes the user priority specified by a priority table according to the adjustment value of a group corresponding to the delay time, compares the changed user priorities, and selects and transmits a frame with a highest changed user priority. ### Claim 13 (depends on 11) The system as claimed in claim 11, wherein the virtual collision handler determines whether the delay time exceeds a threshold value, and selects and transmits the transmission frame most preferentially if any transmission frame has a delay time exceeding the threshold value. ### Claim 14 A wireless communication data transmission method, comprising the steps of: storing received data into a corresponding data buffer according to a user priority; storing a transmission time when transmitting the stored data; driving a timer and determining, when transmitting data, whether a response message is received in response to the data before the timer reaches a specific value; calculating a delay time of the data using the stored transmission time, if the response message is not received until the timer reaches the specific value; and setting a user priority of the data using the calculated delay time to store the data into a data buffer corresponding to the user priority and then to try retransmission. ### Claim 15 (depends on 14) The method as claimed in claim 14, wherein the user priority is set when the data to be transmitted are transferred from an upper layer to a MAC layer and is stored in a MAC header of the data. ### Claim 16 (depends on 14) The method as claimed in claim 14, wherein the transmission time is stored in a delay parameter area provided in a MAC header of the data. ### Claim 17 (depends on 14) The method as claimed in claim 14, wherein the delay time is set to zero if a value measured by the timer is smaller than a default value or is a value greater than the default value if the value measured by the timer is greater than the default value. ### Claim 18 (depends on 15) The method as claimed in claim 15, wherein the user priority is set by dividing the delay time into a plurality of groups, putting an adjustment value to each group, and changing a user priority determined by characteristics of the data according to the adjustment value of a group corresponding to the delay time. ### Claim 19 (depends on 14) The method as claimed in claim 14, wherein the user priority is set such that the data have a top transmission priority if the delay time exceeds a predetermined time period. ### Claim 20 (depends on 14) The method as claimed in claim 14, wherein the user priority is set such that the data have a user priority one level higher than the user priority determined by characteristics of the data if the delay time exceeds a predetermined time period. ### Claim 21 A wireless communication data transmission method for enhancing quality of service of a wireless communication in contention-based channel access mode, the method comprising the steps of: (A) storing a transmission time in a transmission frame to be transmitted; (B) transmitting the transmission frame; (C) examining whether a response frame is received within a predetermined time period; (D) calculating a delay time from the transmission time and setting a user priority of the transmission frame using the delay time, if the response frame is not received within the predetermined time period; (E) determining an AC according to the set user priority; and (F) transmitting the transmission frame to a transmission queue corresponding to the AC. ### Claim 22 (depends on 21) The method as claimed in claim 21, wherein step (D) of setting a user priority is accomplished by dividing a predetermined range of time period into a plurality of groups, putting an adjustment value to each group, and changing a user priority set from a priority table according to the adjustment value of a group corresponding to the delay time. ### Claim 23 (depends on 22) The method as claimed in claim 22, further comprising the steps of: (D′) setting the user priority to zero if the user priority is smaller than zero; and (D″) setting the user priority to seven if the user priority is greater than seven. ### Claim 24 (depends on 23) The method as claimed in claim 23, wherein the transmitting station is an access point, and the receiving station is a terminal device. ### Claim 25 (depends on 23) The method as claimed in claim 23, wherein the transmission frame is a QoS data frame. ### Claim 26 (depends on 21) The method as claimed in claim 21, wherein the wireless communication is in ad-hoc mode, and the transmitting and receiving stations are terminal devices. ### Claim 27 A wireless communication data transmission method, comprising the steps of: calculating a delay time using transmission time information included in received data; storing the received data into a corresponding data buffer in consideration of the delay time and a user priority of the received data; and transmitting data selected in contention mode among data stored in at least one or more data buffers. ### Claim 28 (depends on 27) The method as claimed in claim 27, further comprising the step of storing a transmission time in the data when transmitting the data. ### Claim 29 (depends on 28) The method as claimed in claim 28, wherein the transmission time is stored in a delay parameter area provided in a MAC header of the data. ### Claim 30 (depends on 29) The method as claimed in claim 29, wherein the user priority is set when the data to be transmitted are transferred from an upper layer to a MAC layer and is stored in the MAC header of the data. ### Claim 31 (depends on 27) The method as claimed in claim 27, wherein the delay time is set to zero if a value measured by the timer is smaller than a default value or is a value greater than the default value if the value measured by the timer is greater than the default value. ### Claim 32 (depends on 27) The method as claimed in claim 27, wherein the step of storing the data into a data buffer comprises the step of storing the data into a data buffer whose transmission priority is increased or decreased, as compared with a data buffer corresponding to the user priority, according to the delay time. ### Claim 33 (depends on 27) The method as claimed in claim 27, wherein the step of storing the data into a data buffer comprises the step of storing the data into a data buffer with a top transmission priority, if the delay time exceeds a predetermined time period. ### Claim 34 (depends on 27) The method as claimed in claim 27, wherein the step of storing the data into a data buffer comprises the step of storing the data into a data buffer with a transmission priority one level higher than that of a data buffer corresponding to the user priority. ### Claim 35 A wireless communication data transmission method for enhancing quality of service of a wireless communication in contention-based channel access mode, the method comprising the steps of: (a) storing a transmission time in a transmission frame to be transmitted; (b) transmitting the transmission frame; (c) examining whether a response frame is received within a predetermined time period; (d) setting a user priority of the transmission frame according to a priority table if the response frame is not received within the predetermined time period; (e) determining an AC of the transmission frame using a delay time calculated based on the user priority and the transmission time; and (f) transmitting the transmission frame to a transmission queue corresponding to the AC. ### Claim 36 (depends on 35) The method as claimed in claim 35, wherein step (e) of determining an AC comprises the steps of calculating a delay grade corresponding to the delay time, and determining an AC, to which the transmission frame belongs, according to the delay grade. ### Claim 37 (depends on 35) The method as claimed in claim 35, wherein step (e) of determining an AC comprises the steps of determining whether the delay time exceeds a predetermined time period, and assigning the transmission frame to an AC with a top priority if the delay time exceeds a predetermined time period. ### Claim 38 (depends on 35) The method as claimed in claim 35, wherein step (e) of determining an AC comprises the steps of determining whether the delay time exceeds a predetermined time period, and assigning the transmission frame to an AC with a user priority one level higher than that of an AC corresponding to the user priority of the transmission frame to transmit the transmission frame. ### Claim 39 (depends on 35) The method as claimed in claim 35, wherein the transmission time is stored in a delay parameter area provided in a MAC header of the transmission frame. ### Claim 40 A wireless communication data transmission method, comprising the steps of: storing received data into a corresponding data buffer according to a user priority thereof; having access to a transmission medium to transmit data stored in at least one or more data buffers; and if data stored in two or more data buffers intend to be simultaneously transmitted, determining data to be preferentially transmitted in consideration of a user priority and a delay time of each data and transmitting the determined data. ### Claim 41 (depends on 40) The method as claimed in claim 40, further comprising the step of storing a transmission time in the data when transmitting the data. ### Claim 42 (depends on 41) The method as claimed in claim 41, wherein the transmission time is stored in a delay parameter area provided in a MAC header of the data. ### Claim 43 (depends on 41) The method as claimed in claim 41, wherein the user priority is set when the data to be transmitted are transferred from an upper layer to a MAC layer and is stored in a MAC header of the data. ### Claim 44 (depends on 41) The method as claimed in claim 41, wherein the delay time is set to zero if a value measured by the timer is smaller than a default value or is a value greater than the default value if the value measured by the timer is greater than the default value. ### Claim 45 (depends on 40) The method as claimed in claim 40, wherein the transmission data are determined by changing the user priority of each data in consideration of the delay time and comparing the changed user priorities. ### Claim 46 (depends on 45) The method as claimed in claim 45, wherein the user priority is changed by dividing the delay time into a plurality of groups, putting an adjustment value to each group, and changing the user priority according to the adjustment value. ### Claim 47 (depends on 40) The method as claimed in claim 40, wherein if any data have a delay time exceeding a predetermined time period, the data with the delay time exceeding the predetermined time period are determined to be preferentially transmitted. ### Claim 48 A wireless communication data transmission method for enhancing quality of service of a wireless communication in contention-based channel access mode, the method comprising the steps of: (I) storing a transmission time in a transmission frame to be transmitted; (II) transmitting the transmission frame; (III) detecting whether an internal collision occurs between ACs; (IV) selecting, by a virtual collision handler, a transmission frame to be transmitted in consideration of the transmission time, if the internal collision occurs between the ACs; and (V) transmitting the selected transmission frame. ### Claim 49 (depends on 48) The method as claimed in claim 48, wherein step of (IV) of selecting a transmission frame comprises the steps of dividing a predetermined range of time period into a plurality of groups, putting an adjustment value to each group, changing a user priority specified by a priority table according to the adjustment value of a group corresponding to the delay time, comparing the changed user priorities, and selecting and transmitting a frame with a highest changed user priority. ### Claim 50 (depends on 48) The method as claimed in claim 48, wherein step (IV) of selecting a transmission frame comprising of the steps of determining whether the delay time exceeds a threshold value, and selecting and transmitting the transmission frame most preferentially, if any transmission frame has a delay time exceeding the threshold value.