Data packet transaction timing solution for wireless communication systems

Abstract

The present invention relates to a wireless communication system including a plurality of radio devices. Each of the plurality of radio devices is capable of transmitting and receiving data packets. At least one radio device is configured to determine a length of an ACK gap period for one or more neighboring radio devices based on ACK packets received from the one or more neighboring radio devices and observed ACK packets in response to the transmitted data packets, and adjust its ACK listening duration based on the determined length of the ACK gap period. The present invention also relates to a method for the wireless communication system, a radio device for the wireless communication system, a method for the radio device, a computer program, and a tangible non-volatile computer readable medium.

Description

[Technical Field]

[0001] The present invention relates generally to the technical field of wireless communications, and more particularly to wireless communication systems. [Background technology]

[0002] A wireless communication system, i.e., a wireless communication network, comprises multiple radio devices that can communicate with each other. To communicate with each other, multiple radio devices of a wireless communication system may transmit data packets to one or more other radio devices of the wireless communication system. The transmission of the data packets may be, for example, a unicast transmission, a multicast transmission, or a broadcast transmission. In response to receiving a data packet from another radio device (i.e., a transmitting device), the receiving radio device may transmit an acknowledgement (ACK) packet to the transmitting device. ACK packets are typically used in unicast communications and are also typically used in multicast communications.

[0003] Typically, the performance of a wireless communication system can be significantly affected by the length of a packet transaction. A unicast packet transaction (i.e., a point-to-point packet transaction or packet transaction between two wireless devices) may typically comprise at least a portion of a clear channel assessment (CCA) duration, an actual data packet transmission from a source device (i.e., a transmitting device) to a target device (i.e., a receiving device), an ACK gap period, and an ACK packet transmission from the target device to the source device. During the CCA duration, the source device evaluates whether the channel to be used for transmission is free of congestion, i.e., whether the transmission of the data packet will not interfere with other transmissions already in progress. During the actual data packet transmission, the source device transmits the data packet. During the ACK gap period, the target device processes the reception of the data packet transmitted by the source device and creates an ACK packet. During the ACK packet transmission, the target device transmits the ACK packet to the source device.

[0004] Typically, the duration of a maximum-length data packet transmission and the duration of an ACK packet transmission are fixed for a single modulation scheme. The CCA duration should cover the ACK gap period so that if another pair of wireless devices in the neighborhood has already started a packet transaction, i.e., is already transmitting a data packet, no one will interrupt their packet transaction by starting transmission during their ACK gap period. CCA is often included with some additional random delay to reduce possible collisions between devices starting CCA simultaneously.

[0005] The length of the ACK gap period (and therefore the CCA duration) varies within a wireless communication system because different implementations require different amounts of time to process received data packets and create ACK packets. At least one drawback of varying the length of the ACK gap period is that to avoid interfering with the slowest implementation, all radio devices within the wireless communication system should use the worst-case length of the ACK gap period, i.e., the longest possible length of the ACK gap period that occurs within the wireless communication system. This could cause the wireless communication system to operate at less than optimal performance.

[0006] Therefore, there is a need to develop solutions to improve the performance of wireless communication systems.

[0007] The following presents a simplified summary in order to provide a basic understanding of some aspects of various invention embodiments. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of example embodiments of the invention. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide a wireless communication system, a method, a radio device, a computer program, and a tangible, non-volatile computer-readable medium that improves the performance of a wireless communication system.

[0009] The object of the present invention is achieved by a wireless communication system, a method, a radio device, a computer program, and a tangible, non-volatile computer-readable medium as defined by the respective independent claims. [Means for solving the problem]

[0010] According to a first aspect, there is provided a wireless communication system including a plurality of radio devices, each of which is capable of transmitting and receiving data packets, wherein at least one radio device of the plurality of radio devices is configured to observe, in response to a transmitted data packet, received acknowledgement (ACK) packets from one or more neighboring radio devices belonging to the plurality of radio devices, determine lengths of ACK gap periods for one or more of the neighboring radio devices based on the observed acknowledgement packets, and adjust its ACK listening duration based on the determined lengths of the ACK gap periods for one or more of the neighboring radio devices.

[0011] At least one of the wireless devices may be further configured to adjust its clear channel assessment (CCA) duration based on the determined lengths of the ACK gap periods of one or more of the neighboring wireless devices.

[0012] At least one of the wireless devices may also classify the determined lengths of the ACK gap periods of one or more of the neighboring wireless devices into two or more categories and include, exclude, and / or weight at least one of the two or more categories when adjusting its clear channel assessment duration.

[0013] Alternatively, or in addition, at least one of the wireless devices may be configured to adjust its clear channel assessment duration (210) based on ACK gap duration information received from neighboring wireless devices, and the received ACK gap duration information may include the length of the ACK gap period of the neighboring wireless device itself, the clear channel assessment duration of the neighboring wireless device itself, and / or the length of the ACK gap period of one or more of the neighboring wireless devices determined based on ACK packets observed and received by the neighboring wireless devices.

[0014] Alternatively, or in addition, at least one of the wireless devices may be configured to include its dominant clear channel assessment duration and / or its dominant length of the ACK gap period as a data field in a beacon packet.

[0015] Alternatively, or in addition, at least one of the wireless devices may be configured to provide its dominant clear channel assessment duration and / or its dominant length of the ACK gap period to at least one new wireless device associated with the wireless communications system as part of an associated packet exchange.

[0016] Each transmitted data packet may include a sequence number that is incremented only when a new data packet is ready for transmission.

[0017] Additionally, at least one radio device among the plurality of radio devices may be configured to adjust the length of its ACK packet transmission period and / or its ACK gap period in response to receiving data packets having the same sequence number.

[0018] At least one of the wireless devices may be configured to observe the ACK packets received from one or more of the neighboring wireless devices during an observation time window.

[0019] At least one of the wireless devices may also be configured to adjust the length of the observation time window based on a rate of change within the wireless communications system.

[0020] According to a second aspect, there is provided a method for a wireless communication system including a plurality of radio devices, each of which is capable of transmitting and receiving a data packet, wherein at least one of the plurality of radio devices observes, in response to the transmitted data packet, received acknowledgement (ACK) packets from one or more neighboring radio devices belonging to the plurality of radio devices, determines, by the at least one radio device of the plurality of radio devices, lengths of ACK gap periods for one or more of the neighboring radio devices based on the observed ACK packets, and adjusts, by the at least one radio device of the plurality of radio devices, its ACK listening period based on the determined lengths of the ACK gap periods for one or more of the neighboring radio devices.

[0021] According to a third aspect, there is provided a radio device for a wireless communication system, the radio device observing acknowledgement (ACK) packets received from one or more neighboring radio devices in response to transmitted data packets, determining lengths of ACK gap periods for one or more of the neighboring radio devices based on the observed ACK packets, and adjusting its ACK listening duration based on the determined lengths of the ACK gap periods for one or more of the neighboring radio devices.

[0022] According to a fourth aspect, there is provided a method for a radio device in a wireless communication system, the method comprising: observing, by the radio device, acknowledgement (ACK) packets received from one or more neighboring radio devices in response to the transmitted data packets; determining, by the radio device, lengths of ACK gap periods for one or more of the neighboring radio devices based on the observed ACK packets; and adjusting, by the radio device, its ACK listening duration based on the determined lengths of the ACK gap periods for one or more of the neighboring radio devices.

[0023] According to a fifth aspect, there is provided a computer program comprising instructions which, when executed by the wireless device, cause the wireless device to perform at least the steps of the method described above.

[0024] According to a sixth aspect, there is provided a tangible, non-volatile computer readable medium containing the computer program as described above. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 illustrates a schematic diagram of an example of a wireless communication system according to the present invention. [Figure 2A] FIG. 2A illustrates an example timing diagram for a data packet transaction with acknowledgements between two wireless devices. [Figure 2B] FIG. 2B illustrates an example timing diagram for a data packet transaction with acknowledgements between two wireless devices. [Figure 3] FIG. 3 shows a schematic diagram of an example of a method according to the invention. [Figure 4] FIG. 4 shows a schematic representation of another example of a method according to the invention. [Figure 5] FIG. 5 shows an example of a wireless device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] Various exemplary and non-limiting embodiments of the present invention, both as to structure and method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplary and non-limiting embodiments when read in connection with the accompanying drawings.

[0027] The verb "to comprise" is used herein as an open limitation that neither excludes nor requires the presence of unrecited features. Features recited in dependent claims may be freely combined with each other unless otherwise stated. Furthermore, throughout this specification, it is to be understood that the use of the singular, such as "a," does not exclude the plural.

[0028] Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the accompanying figures.

[0029] 1 schematically illustrates an example of a wireless communication system, i.e., a wireless communication network 100, in accordance with the present invention. The exemplary wireless communication system 100 of FIG. 1 is implemented in a mesh topology. However, the present invention is not limited to a mesh topology, and the wireless communication system 100 may be implemented in any other network topology, such as a star topology, a ring topology, a hybrid topology, or any other network topology. Some non-limiting examples of wireless communication technologies to which the wireless communication system 100 may be applied may include, but are not limited to, a Bluetooth Low Energy (BLE) mesh network, a Public Land Mobile network (PLMN), a Wireless Local Area network (WLAN), a cellular network, or a wireless mesh network, e.g., a wireless sensor network, and / or any other wireless network.

[0030] The wireless communication system 100 comprises multiple wireless devices 102, e.g., wireless nodes. Each of the multiple wireless devices 102 of the wireless communication system 100 is capable of transmitting and receiving one or more data packets 220. The term “data packet” refers to any radio transmission that carries information required by the wireless communication system 100 itself and / or higher layer applications using the wireless communication system 100. A data packet 220 may be transmitted to and / or received from one or more other wireless devices 102 of the wireless communication system 100 for communication with the one or more other wireless devices 102. Transmission of a data packet 220 may comprise a unicast transmission of the data packet 220 and / or a multicast transmission of the data packet 220. Unicast transmission may be used in point-to-point communication, i.e., communication between two wireless devices. Multicast transmission may be used in multicast communication, i.e., communication between one transmitting wireless device and a limited number of receiving wireless devices. The wireless communication system 100 may be part of a gateway to another network, for example the Internet, and may include at least one sink device that may deliver data to and from the wireless communication system 100. In the example of Figure 1, two radio devices 102, indicated by black circles, are acting as sink devices.

[0031] In response to receiving a data packet 220 from another wireless device, i.e., the transmitting device 202, the receiving wireless device 204 can transmit an acknowledgment (ACK) packet 240 to the transmitting wireless device 202 to indicate whether the data packet 220 was correctly received. The term "ACK packet" is used throughout this specification to refer to any wireless transmission that carries information as feedback for receiving or not receiving the data packet 220. The receiving wireless device 202 performs an error detection calculation process to confirm whether the data packet 220 was correctly received and transmits an ACK packet 240 indicating the result of the error detection calculation process. The error detection calculation process may be, for example, a cyclic redundancy check (CRC) process or any other suitable error detection process. Depending on the result of the error detection calculation, the ACK packet 240 may be a positive ACK packet, i.e., an ACK packet indicating correct reception of the data packet 220, or a negative ACK packet, i.e., an ACK packet indicating incorrect reception of the data packet 220. As used throughout this specification, the terms "acknowledgment packet" and "ACK packet" refer to any type of acknowledgment packet, either positive or negative. In some cases, a negative ACK packet 240 is not transmitted. Thus, if the transmitting wireless device 202 does not receive an ACK packet 240 from the receiving device 204 in response to a transmitted data packet 220, it may be an indication of erroneous reception of the data packet 220, or an indication that the receiving wireless device 204 did not receive the data packet 220 at all. Alternatively, or in addition, possibly instead of transmitting a separate ACK packet 240 in response to receiving each data packet 220, the receiving wireless device 202 may transmit one common ACK packet 240 to the transmitting wireless device 202 in response to receiving two or more data packets 220 from the same transmitting device 202.Alternatively or additionally, in some cases, if the transmitting wireless device 202 does not receive an ACK packet 240 from the receiving wireless device 204 and / or the received ACK packet 240 is negative, the transmitting wireless device 202 may retransmit the data packet 220 to the receiving wireless device 204 until a positive ACK packet 240 is received or until a predefined limit of retransmissions of the same data packet 220 is met. The transmission of the data packet 220 and the ACK packet 240 will now be further described with reference to Figures 2A and 2B, which show example timings of a data packet transaction with an ACK packet 240.

[0032] 2A illustrates a simple timing example of a data packet transaction using an ACK packet 240 between two wireless devices 102. The two wireless devices 102 may comprise a first wireless device, i.e., a transmitting wireless device or source device 202, and a second wireless device, i.e., a receiving wireless device or target wireless device 204. FIG. 2A illustrates the main phases of a data packet transaction with an ACK packet. The main phases of a data packet transaction with an ACK packet may comprise at least the following phases: a clear channel assessment (CCA) duration 210, a data packet 220 transmission period, an ACK gap period 230, and an ACK packet 240 transmission period. The example of FIG. 2A introduces the main phases of a data packet transaction between two wireless devices 102 without specifying the operation of the two devices during the data packet transaction.

[0033] During the CCA duration 210, the first radio device 202 performs a CCA process, during which the first radio device 202 evaluates whether the channel to be used for transmitting the data packet 220 is free of congestion, i.e., whether the transmission of the data packet 220 will not interfere with other transmissions already in progress. During the transmission period of the data packet 220, the data packet 220 is transmitted from the first radio device 202 to the second radio device 204. During the ACK gap period 230, the second radio device 204 processes the reception of the data packet 220 transmitted by the first radio device 202 and generates an ACK packet 240, for example, according to the results of the error detection calculation described above. During the transmission period of the ACK packet 240, the ACK packet 240 is transmitted from the second radio device 204 to the first radio device 202. In the example of FIG. 2A , T1 represents the period the first radio device 202 needs to prepare before it is ready to receive the ACK packet 240, i.e., the first radio device 202 switches from the transmit mode Tx to the receive mode Rx. In the example of Figure 2A, T2 represents the time period during which the first wireless device 202 maintains its receive mode Rx while waiting for the start of transmission of the ACK packet 240 from the second wireless device 204. In the example of Figure 2A, if transmission of the ACK packet 240 begins during T2 but is not completed during T2, then T3 represents an additional time period to receive the entire ACK packet 240.

[0034] 2B illustrates another non-limiting timing example of a data packet transaction using an ACK packet between two wireless devices 102. Similar to the example of FIG. 2A, the two wireless devices 102 may comprise a first wireless device, i.e., a transmitting wireless device or source wireless device 202, and a second wireless device, i.e., a receiving wireless device or target wireless device 204. The example of FIG. 2B illustrates a more detailed timing example of a data packet 220 transaction with an ACK packet 240 between two wireless devices 102, with the activities, i.e., operations, of the first wireless device 202 and the second wireless device 204 separated, i.e., the data packet transaction is shown separately from the perspective of the first wireless device 202 and the second wireless device 204. The top diagram, i.e., upper graph, of FIG. 2B illustrates the activity of the second wireless device 204 during the data packet transaction, and the bottom diagram, i.e., lower graph, of FIG. 2B illustrates the activity of the first wireless device 204 during the data packet transaction. Rx refers to the receiving mode of the device, and Tx refers to the transmitting mode of the device in the example of FIG. 2B.

[0035] At time t1, the CCA duration 210 begins, during which the first wireless device 202 performs the CCA process. At time t2, the first wireless device 202 ends the process. The period between time t1 and time t2 represents the CCA duration 210 of the first wireless device 202, i.e., the duration of the CCA process of the first wireless device 202. From time t2 to time t3, the first wireless device 202 switches from the receive mode Rx to the transmit mode Tx. At time t3, the first wireless device 202 starts transmitting the data packet 220, and at time t4, the transmission of the data packet 220 ends. The period between time t3 and time t4 represents the transmission period of the data packet 220 of the first wireless device 202. The time between time t4 and time t5 corresponds to time T1 described above with reference to the example of FIG. 2A. That is, between time t4 and time t5, the first radio device 202 prepares to receive an ACK packet, i.e., the first radio device 202 switches from transmit mode Tx to receive mode Rx. At time t5, the first radio device 202 begins an ACK listening phase. During the ACK listening phase, the first radio device 202 waits to receive an ACK packet 240 transmission from the second radio device 204. ACK listening duration 250 represents the duration of the ACK listening phase, i.e., the period during which the first radio device 202 waits to receive an ACK packet 240 transmission from the second radio device 204. At time t6, the first radio device 202 begins receiving the ACK packet 240 from the second device 204, and at time t7, reception of the ACK packet 240 ends. The first radio device 202 waits the entire ACK listening duration 250 before determining a response, i.e., that an ACK packet 240 is not coming. ACK listening duration 250 corresponds to period T2 described above with reference to the example of Figure 2A. The first wireless device 202 may extend ACK listening duration 250 until the end of the transmission of ACK packet 240 to reduce data packet retransmissions if the transmission of ACK packet 240 by the second wireless device 204 begins near the end of the first wireless device 202's ACK listening duration 250. The possible extended duration of ACK listening duration 250 represents the additional period T3 described above with reference to the example of Figure 2A.In the example of FIG. 2B, reception of ACK packet 240 finishes during ACK listening duration 250, and therefore, additional time period T3 is not required in the example of FIG. 2B.

[0036] At the start of a data packet transaction, the second radio device 204 is in a receive mode Rx, waiting to receive one or more data packets 220 from the first radio device 202. At time t3, the second radio device 204 begins receiving the data packets 220 from the first device 202, and at time t4, reception of the data packets 220 ends. At time t4, the second radio device 204 begins an ACK gap period 230 phase. During the ACK gap period 230 phase, the second radio device 204 processes the reception of the data packets 220 transmitted by the first radio device 202 and generates an ACK packet 240, for example, according to the results of the error detection calculations described above. The length of the ACK gap period 230 represents the duration of the ACK gap period 230 phase. During the ACK gap period 230, the second radio device 202 switches from the receive mode Rx to the transmit mode Tx. At time t6, the second radio device 204 starts transmitting the ACK packet 240, and ends transmitting the ACK packet 240 at time t7. The period between time t6 and time t7 represents the transmission period of the ACK packet 240 of the second radio device 204.

[0037] A timing method according to the present invention may be used in the wireless communication system 100 described above. An example of a timing method according to the present invention will now be described with reference to Figure 3, which illustrates an example of the present invention generally as a flow chart. The method will be described primarily with reference to one radio device 102, i.e., the first radio device 202, belonging to the wireless communication system 100. However, each radio device 102, 202, 204 in the wireless communication system 100 may perform the method steps. Each radio device 102, 202, 204 in the wireless communication system 100 may transmit at least one data packet 220 to one or more other radio devices, i.e., one or more neighboring radio devices 102, 202, 204, and may receive at least one data packet 220 from one or more other devices 102, 202, 204 as described above. In other words, each radio device 102, 202, 204 of the wireless communication system 100 can provide, by means of its data transfer unit 506, bidirectional wireless communication with one or more other radio devices, i.e., one or more neighboring radio devices 102, 202, 204 in the wireless communication system 100. In other words, each radio device 102, 202, 204 of the wireless communication system 100 can operate as a first radio device 202 and / or a second radio device 204.

[0038] The term "neighboring wireless device" refers throughout this specification to a wireless device whose wireless transmissions can be detected by a receiving wireless device. The expanded meaning of the term "neighboring wireless device" includes devices near a wireless device, i.e., two-hop neighboring devices, three-hop neighboring devices, four-hop neighboring devices, and / or multi-hop neighboring devices. The term "neighborhood of a wireless device" refers throughout this application to one or more wireless devices whose wireless transmissions can be detected by a receiving wireless device. The expanded meaning of the term "neighborhood of a wireless device" includes devices near a wireless device, i.e., multi-hop neighboring devices, such as two-hop neighboring devices, three-hop neighboring devices, four-hop neighboring devices, etc.

[0039] In step 310, the first radio device 202 observes ACK packets 240 received from one or more neighboring radio devices 102, 204 belonging to a plurality of radio devices in the wireless communication system 100. The ACK packets 240 are received by the first radio device 202 in response to transmitted data packets 220. In other words, the first radio device 202 transmits one or more data packets 220 to one or more neighboring radio devices 102, 204 and observes one or more received ACK packets 240 from the one or more neighboring radio devices 102, 204, respectively.

[0040] The first wireless device 202 may observe ACK packets 240 received from one or more neighboring wireless devices 102, 204 during the observation time window. The first wireless device 202 may adjust the length of the observation time window based on the rate of change within the wireless communication system 100. In other words, the first wireless device 202 may adjust the length of the observation time window based on how fast changes may occur within the wireless communication system 100. For example, if one or more of the multiple wireless devices 102 begins to move faster or more than before, the first wireless device 202 may shorten the length of the observation time window to take into account only the most recent observed ACK packets 240.

[0041] In step 320, the first wireless device 202 determines the length of the ACK gap period 230 of one or more neighboring wireless devices 102, 204 based on the observed ACK packets 240. Determining the length of the ACK gap period 230 of each of the one or more neighboring wireless devices 102, 204 may comprise, for example, measuring the time elapsed from the end of the data packet 220 transmission to the start of the reception of the respective ACK packet 240.

[0042] At step 330, the first radio device 202 adjusts its ACK listening duration 250 based on the determined lengths of the ACK gap periods 230 of one or more neighboring radio devices. This improves performance and reduces power consumption of the wireless communication system 100. Adjusting the ACK listening duration 250 of the first radio device 202 may comprise, for example, determining a maximum length of the ACK gap period 230 based on the determined lengths of the ACK gap periods 230 of one or more neighboring radio devices, and adjusting the ACK listening duration 250 of the first radio device 202 according to the determined maximum length of the ACK gap period 230. The adjustment may comprise increasing or decreasing the ACK listening duration 250 of the first radio device 202. For example, if the determined maximum length of the ACK gap period 230 is substantially shorter, the ACK listening duration 250 of the first radio device 202 may be reduced, which improves performance of the wireless communication system 100 and reduces power consumption of the first radio device 202. Alternatively, if the determined maximum length of the ACK gap period 230 is substantially long, the ACK listening duration 250 of the first wireless device 202 may be increased.

[0043] In optional step 340, the first radio device 202 may further adjust its CCA duration 210, thereby improving performance of the wireless communication system 100. The CCA duration 210 of the first radio device 202 should cover the length of the ACK gap period 230 of one or more neighboring radio devices 102, 202, so that if at least one other radio device pair in the vicinity has already initiated a data packet transaction, i.e., is already transmitting a data packet, the first device 202 does not interrupt the packet transaction of the at least one other radio device pair by starting to transmit a data packet 220 during the ACK gap period 230 of the at least one other radio device pair. The at least one other radio device pair may, for example, be at least one second transmitting radio device and at least one second receiving radio device belonging to one or more neighboring radio devices of the first radio device 204. The adjustment may comprise increasing or decreasing the CCA duration 210 of the first radio device 202.

[0044] According to one example of the present invention, in step 340, the first wireless device 202 may adjust its CCA duration 210 based on the determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices. Adjusting the CCA duration 210 of the first wireless device 202 may comprise, for example, determining a maximum length of the ACK gap period 230 based on the determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices and adjusting the CCA duration 210 of the first wireless device 202 according to the determined maximum length of the ACK gap period 230. For example, if the maximum length of the ACK gap period 230 is substantially short, the CCA duration 210 of the first wireless device 202 may be reduced, which improves performance of the wireless communication system 100. Alternatively, if the determined maximum length of the ACK gap period 230 is substantially long, the CCA duration 210 of the first wireless device 202 may be increased. Furthermore, the CCA duration may be added with a random delay, for example, in a wireless communication system in which CCA start times are likely to be simultaneous.

[0045] Alternatively, or in addition, in step 340, the first wireless device 202 may adjust its CCA duration 210 based on ACK gap period 230 information received from nearby wireless devices, i.e., reporting wireless devices. The received ACK gap period 230 information may include, for example, the length of the reporting wireless device's own ACK gap period 230, the reporting wireless device's own CCA duration 210, and / or the length of the ACK gap period 230 of one or more neighboring wireless devices of the reporting wireless device as determined based on received ACK packets 240 observed by the reporting wireless device.

[0046] According to one example of the present invention, the first wireless device 202 may further classify (410) the determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices 102, 204 into two or more categories. The determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices 102, 204 may be classified based on, for example, the delay in transmitting an ACK packet 240 and / or the nature of the determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices 102, 204, e.g., the nature may be deterministic. For example, if the second wireless device 204 prioritizes the transmission or reception of one or more beacon messages via ACK packet 240 transmission, there may be, for example, a longer delay in transmitting an ACK packet 240. The first wireless device 202 may further include, exclude, and / or weight at least one of the two or more categories when adjusting its CCA duration 210 in step 340. This allows taking into account only the most relevant determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices 102, 204 in adjusting the CCA duration 210. Figure 4 schematically illustrates an example of a method in accordance with the present invention, including step 410 of optionally classifying the determined lengths of the ACK gap periods 230 of one or more neighboring wireless devices 102, 204 into two or more categories. Furthermore, in the example of Figure 4, when the first wireless device 202 adjusts its CCA duration 210 in step 340, it includes, excludes, and / or weights at least one of the two or more categories.

[0047] According to one example of the present invention, the first wireless device 202 may include its dominant CCA duration 210, i.e., the CCA duration 210 currently being used by the first wireless device 202, and / or its dominant length of the ACK gap period 230, i.e., the length of the ACK gap period 230 currently being used by the first wireless device 202, as a data field in a beacon packet. The first wireless device 202 may broadcast the beacon packet to one or more neighboring wireless devices 102, 202, 204 belonging to the wireless communication system 100. This may enable one or more neighboring wireless devices 102, 202 to adjust their CCA duration 210 and / or ACK listening duration 250 with less independent observation and / or more quickly. The one or more neighboring wireless devices 102, 202, 204 may adjust their CCA duration 210 and / or their ACK listening duration 250 in response to receiving a beacon message from the first wireless device 202. In other words, one or more neighboring wireless devices 102, 202, 204 may adjust their CCA duration 210 and / or their ACK listening duration 250 based on the length of the CCA duration 210 and / or ACK gap period 230 included in the beacon packet broadcast by the first wireless device 202.

[0048] Alternatively, or in addition, the first wireless device 202 may provide its dominant CCA duration 210 and / or its dominant length of the ACK gap period 230 to at least one new wireless device associated with the wireless communication system 100 as part of an association packet exchange when the at least one new wireless device associates, i.e., joins, the wireless communication system 100. This may allow the at least one new wireless device to adjust their CCA duration 210 and / or ACK listening duration 250 with less independent observation and / or more quickly. For example, the first wireless device 202 may include its dominant CCA duration 210 and / or its dominant length of the ACK gap period 230 in an association packet, e.g., an association message. The first wireless device 202 may provide, e.g., transmit, an association packet to the at least one new wireless device associated with the wireless communication system 100 as part of an association packet exchange when the at least one new wireless device associates, i.e., joins, the wireless communication system 100. At least one new wireless device associated with wireless communication system 100 may adjust their CCA duration 210 and / or their ACK listening duration 250 in response to receiving an associated packet from first wireless device 202, for example, in response to an associated packet exchange with first wireless device 202. In other words, at least one new wireless device associated with wireless communication system 100 may adjust their CCA duration 210 and / or their ACK listening duration 250 based on the length of CCA duration 210 and / or ACK gap period 230 provided by first wireless device 202.

[0049] According to one example of the present invention, each transmitted data packet 220 may include a sequence number that is incremented only when a new data packet 220 is prepared for transmission. In other words, the sequence number is maintained the same for retransmissions of the data packet 220 and incremented for transmissions of new data packets 220. Each wireless device 102, 202, 204 in the wireless communication system 100 may further adjust the length of its ACK gap period 230 and / or its ACK packet 240 transmission period in response to receiving a data 220 packet with the same sequence number. According to a non-limiting example, each wireless device 102, 202, 204 may adjust the length of its ACK gap period 230 and / or its ACK packet 240 transmission period in response to receiving a predefined number of data packets 220 with the same sequence number. The use of sequence numbers may enable detection of possible timing mismatches with multiple wireless devices 102. It may make it possible to identify too early or too late ACK packets 240, for example, by detecting persistent retransmissions of data packets 220 with the same sequence number. For example, if the first radio device 202 switches on its receive mode Rx after the second radio device 204 has already started transmitting the respective ACK packets 240, the first radio device 202 will miss receiving the ACK packets 240.

[0050] FIG. 5 illustrates an example of a wireless device (apparatus) 102, 202, 204 according to the present invention. The wireless device 102, 202, 204 includes a processing unit 502 configured to execute instructions initiated by a user and / or a computer program (software) and to process data to implement applications and communication protocols. The processing unit 502 may include at least one processor, e.g., one, two, or three processors. The wireless device 102, 202, 204 further includes a memory unit 504 for storing and maintaining data. The data may be instructions, computer programs, and data files. The memory unit 504 may include at least one memory, e.g., one, two, or three memories.

[0051] The wireless device 102, 202, 204 further comprises a data transfer unit 506 and an antenna unit 508 for providing bidirectional wireless communication with at least one other wireless device 102, 202, 204. The wireless device 102, 202, 204 can use the data transfer unit 506 to transmit data packets 220, ACK packets 240, commands, requests, messages, and data to at least one of the other wireless devices 102, 202, 204 in the wireless communication system 100 via the antenna unit 508. The data transfer unit 506 also receives data packets 220, ACK packets 240, commands, requests, messages, and data from at least one of the other wireless devices 102, 202, 204 in the wireless communication system 100 via the antenna unit 508. The wireless device 102, 202, 204 may further comprise a power supply unit 510. The power supply section 510 includes components for powering the radios 102, 202, 204, such as a battery and a regulator.

[0052] The memory unit 504 includes a data transfer application for operating a data transfer unit 506 , an antenna application for operating an antenna unit 508 , and a power supply application for operating a power supply unit 510 .

[0053] The memory unit 504 also comprises a timing application, i.e., computer program 505, which comprises instructions that are executed by a computer, e.g., wireless device 102, 202, 204, by means of the processing unit 502, i.e., that when executed by a computer are configured to perform at least the operations, i.e., method steps, of the wireless device 102, 202, 204 described above, i.e., to use at least one of the portions 506, 508, 510 to perform at least the operations, i.e., method steps.

[0054] The computer program 505 may be stored on a non-legal, tangible computer readable medium, such as a USB stick or a CD-ROM disk, for example.

[0055] The specific examples provided in the above description should not be construed as limiting the applicability and / or interpretation of the appended claims. The lists and groups of examples provided in the above description are not exhaustive unless expressly stated otherwise.

Claims

1. A wireless communication system (100) including a plurality of radio devices (102, 202, 204), each of said plurality of wireless devices (102, 202, 204) being capable of transmitting and receiving data packets (220); At least one wireless device (102, 202, 204) of the plurality of wireless devices observing acknowledgement (ACK) packets (240) received from one or more neighboring wireless devices (102, 202, 204) belonging to said plurality of wireless devices (102, 202, 204) in response to the transmitted data packets (220); determining a length of an ACK gap period (230) for one or more of the neighboring wireless devices (102, 202, 204) based on the observed acknowledgment (ACK) packets (240); the length of the ACK gap period (230) represents the time period during which the neighboring wireless device processes the receipt of the data packet (220) transmitted by the wireless device (102, 202, 204) and generates the acknowledgment (ACK) packet (240); adjusting an ACK listening duration (250) of the wireless device (102, 202, 204) based on the determined length of the ACK gap period (230) of one or more of the neighboring wireless devices (102, 202, 204); It is configured as follows: A wireless communication system (100).

2. At least one of the wireless devices (102, 202, 204) is further configured to adjust a clear channel assessment (CCA) duration (210) of the wireless device (102, 202, 204) based on the determined length of the ACK gap period (230) of one or more of the neighboring wireless devices (102, 202, 204). The wireless communication system (100) of claim 1.

3. At least one of the wireless devices (102, 202, 204) classifying the determined lengths of the ACK gap periods (230) of one or more of the neighboring wireless devices (102, 202, 204) into two or more categories; including, excluding, and / or weighting at least one of two or more of the categories when adjusting the clear channel assessment (CCA) duration (210) of the wireless device (102, 202, 204); The wireless communication system (100) of claim 2.

4. at least one of the wireless devices (102, 202, 204) is configured to adjust a clear channel assessment (CCA) duration (210) of the wireless device (102, 202, 204) based on ACK gap duration (230) information received from a neighboring wireless device (102, 202, 204); The received ACK gap period (230) information includes the length of the ACK gap period (230) of the neighboring wireless device itself, the clear channel assessment (CCA) duration (210) of the neighboring wireless device itself, and / or the length of the ACK gap period (230) of one or more neighboring wireless devices of the neighboring wireless device determined based on an acknowledgement (ACK) packet (240) observed and received by the neighboring wireless device. A wireless communication system (100) according to any one of claims 1 to 3.

5. At least one of the wireless devices (102, 202, 204) is configured to include, as a data field in a beacon packet, a dominant clear channel assessment (CCA) duration (210) of the wireless device (102, 202, 204) and / or a dominant length of an ACK gap period (230) of the wireless device (102, 202, 204). A wireless communication system (100) according to any one of claims 1 to 4.

6. at least one of the wireless devices (102, 202, 204) is configured to provide the wireless device's (102, 202, 204) dominant clear channel assessment (CCA) duration (210) and / or the wireless device's (102, 202, 204) dominant length of the ACK gap period (230) to at least one new wireless device associated with the wireless communication system (100) as part of an associated packet exchange; A wireless communication system (100) according to any one of claims 1 to 5.

7. Each transmitted data packet (220) contains a sequence number that is incremented only when a new data packet (220) is prepared for transmission; A wireless communication system (100) according to any one of claims 1 to 6.

8. and wherein at least one wireless device (102, 202, 204) of the plurality of wireless devices is configured to adjust, in response to receiving a data packet (220) having the same sequence number, a duration of an acknowledgement (ACK) packet (240) transmission period of the wireless device (102, 202, 204) and / or a duration of an ACK gap period (230) of the wireless device (102, 202, 204). The wireless communication system (100) of claim 7.

9. At least one of the wireless devices (102, 202, 204) is configured to observe the acknowledgement (ACK) packets (240) received from one or more of the neighboring wireless devices (102, 202, 204) during an observation time window. A wireless communication system (100) according to any one of claims 1 to 8.

10. 10. The wireless communication system (100) of claim 9, wherein at least one of the radio devices (102, 202, 204) is configured to adjust the length of the observation time window based on a rate of change within the wireless communication system (100).

11. A method for a wireless communication system (100) including a plurality of radio devices (102, 202, 204), comprising: each of the plurality of wireless devices (102, 202, 204) being capable of transmitting and receiving data packets (220); In response to the transmitted data packet (220), at least one wireless device of the plurality of wireless devices observes (310) an acknowledgement (ACK) packet (240) received from one or more neighboring wireless devices belonging to the plurality of wireless devices; At least one of the wireless devices determines (320) a length of an ACK gap period (230) of one or more of the neighboring wireless devices based on observed acknowledgment (ACK) packets (240); the length of the ACK gap period (230) represents the time period during which the neighboring wireless device processes the receipt of the data packet (220) transmitted by the wireless device (102, 202, 204) and generates the acknowledgment (ACK) packet (240); and at least one of the plurality of wireless devices adjusts (330) an ACK listening period (250) of the wireless device (102, 202, 204) based on the determined lengths of the ACK gap periods (230) of one or more of the neighboring wireless devices. A method for a wireless communication system (100).

12. A radio device (102, 202, 204) for a wireless communication system (100), comprising: The wireless device (102, 202, 204) Observing acknowledgement (ACK) packets (240) received from one or more neighboring wireless devices (102, 202, 204) in response to the transmitted data packets (220); determining a length of an ACK gap period (230) for one or more of the neighboring wireless devices (102, 202, 204) based on the observed acknowledgment (ACK) packets (240); the length of the ACK gap period (230) represents the time period during which the neighboring wireless device processes the receipt of the data packet (220) transmitted by the wireless device (102, 202, 204) and generates the acknowledgment (ACK) packet (240); adjusting an ACK listening duration (250) of the wireless device (102, 202, 204) based on the determined length of the ACK gap period (230) of one or more of the neighboring wireless devices (102, 202, 204); Wireless device (102, 202, 204).

13. In response to the transmitted data packet (220), the wireless device (102, 202, 204) observes (310) an acknowledgement (ACK) packet (240) received from one or more neighboring wireless devices; determining (320) a length of an ACK gap period (230) for one or more of the neighboring wireless devices based on the observed acknowledgment (ACK) packets (240); the length of the ACK gap period (230) represents the time period during which the neighboring wireless device processes the receipt of the data packet (220) transmitted by the wireless device (102, 202, 204) and generates the acknowledgment (ACK) packet (240); and adjusting (330) an ACK listening duration (250) of the wireless device (102, 202, 204) based on the determined length of the ACK gap period (230) of one or more of the neighboring wireless devices. A method for a radio device (102, 202, 204) in a wireless communication system (100).

14. A computer program (505) comprising instructions which, when executed by the wireless device (102, 202, 204) of claim 12, cause the wireless device (102, 202, 204) to perform at least the steps of the method of claim 13.

15. 15. A tangible, non-volatile computer readable storage medium containing the computer program (505) of claim 14.

Images