CN118019096A - Control method for wireless communication module for PPDU end time alignment - Google Patents

Abstract

The invention provides a control method for a wireless communication module for PPDU end time alignment. A control method of a wireless communication module, wherein the control method comprises the steps of: receiving target end time information of the PPDU, and estimating symbol count of the PPDU according to the target end time information; determining a duration of a packet extension of the PPDU; refining at least one of a fill factor, a duration of a packet extension, and a symbol count of the PPDU, wherein the fill factor indicates invalid data information of the PPDU; generating an alignment setting including a final symbol count of the PPDU, a duration of the packet extension, and a fill factor of the PPDU; and aggregating a plurality of MPDUs to generate the PPDU according to the alignment setting.

Description

Control method for wireless communication module for PPDU end time alignment

Cross Reference to Related Applications

The present application claims the benefit of U.S. provisional application No.63/383,110 filed on 10/11/2022. The content of this application is incorporated herein by reference.

Technical Field

The present disclosure relates generally to wireless communication modules and associated control methods, and more particularly to wireless communication modules and associated control methods for PPDU end time alignment.

Background

IEEE 802.11be defines a plurality of link operations that allow an Access Point (AP) and a station to communicate with each other by using two or more links. Due to hardware limitations, such as the ability of Radio Frequency (RF) filters between the RF bands within the station, the AP/station may operate in either synchronous or asynchronous mode. The synchronization mode is also referred to as a non-simultaneous transmit and receive (NSTR) mode, i.e., the AP/station cannot simultaneously transmit and receive data via multiple links. The asynchronous mode is also referred to as a Simultaneous Transmission and Reception (STR) mode, i.e., an AP/station may simultaneously transmit and receive data via a plurality of links, but the AP/station does not need to simultaneously transmit data by using a plurality of links.

Regarding the NSTR mode, IEEE 802.11be also defines a physical layer protocol data unit (PPDU) end time alignment requirement that, when a plurality of PPDUs are simultaneously transmitted via a plurality of links, respectively, their end times should be aligned, and that all differences between end times of PPDUs simultaneously transmitted between each pair of the plurality of links be less than or equal to a specific time in order to avoid interference between pairs of the plurality of links. However, since a given length (in units of time) of a PPDU to be transmitted may not be the same as an actual transmission time of the PPDU, a plurality of PPDUs may not be aligned accurately.

Disclosure of Invention

It is, therefore, an object of the present invention to provide a wireless communication method that can determine a proper symbol count and a duration of Packet Extension (Packet Extension) for a PPDU end time alignment mechanism in a PPDU to solve the above-mentioned problems.

According to an embodiment of the present invention, a control method of a wireless communication module, the control method includes: receiving target end time information of the PPDU, and estimating a symbol count of the PPDU according to the target end time information; determining a duration of a packet extension of the PPDU; refining an alignment setting comprising at least one of a fill factor, a duration of the packet extension, and the symbol count of the PPDU, wherein the fill factor indicates invalid data information of the PPDU; generating an alignment setting comprising a final symbol count of the PPDU, a duration of the packet extension, and the fill factor of the PPDU; and aggregating a plurality of media access control protocol data units MPDUs to generate the PPDU according to the alignment setting.

According to one embodiment of the invention, a circuit of a wireless communication module is registered to perform the steps of: receiving target end time information of a physical layer protocol data unit (PPDU), and estimating a symbol count of the PPDU according to the target end time information; determining a duration of a packet extension of the PPDU; refining an alignment setting comprising at least one of a fill factor, a duration of the packet extension, and the symbol count of the PPDU, wherein the fill factor indicates invalid data information of the PPDU; generating an alignment setting comprising a final symbol count of the PPDU, a duration of the packet extension, and the fill factor of the PPDU; and aggregating a plurality of media access control protocol data units MPDUs to generate the PPDU according to the alignment setting.

These and other objects of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the various drawing figures and drawings.

Drawings

Fig. 1 is a diagram illustrating a wireless communication system according to one embodiment of the present invention.

Fig. 2 is a control method of a wireless communication module according to an embodiment of the present invention.

Fig. 3 illustrates a flowchart of a PPDU end time alignment operation according to an embodiment of the present invention.

Fig. 4 illustrates a forced-extra-symbol (fragment) mechanism according to one embodiment of the invention.

Fig. 5 illustrates a forced-extra-symbol (fragment) mechanism according to one embodiment of the invention.

Fig. 6 is a diagram of circuitry within a wireless communication module according to one embodiment of the invention.

Fig. 7 is a diagram of circuitry within a wireless communication module according to one embodiment of the invention.

Detailed Description

Certain terms are used throughout the following description and claims to refer to particular system components. As will be appreciated by those skilled in the art, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to …". The term "couple" is intended to mean either an indirect or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

Fig. 1 is a diagram illustrating a wireless communication system according to one embodiment of the present invention. As shown in fig. 1, the wireless communication system includes an Access Point (AP) 110 and at least one station, such as 120. AP 110 is a Wi-Fi access point that allows other wireless devices, such as station 120, to connect to a wired network, and AP 110 primarily includes processing circuitry 112 and wireless communication module 114. Station 120 is a Wi-Fi station that includes processing circuitry 122 and a wireless communication module 124, and station 120 may be a cellular telephone, tablet, notebook, or any other electronic device capable of wirelessly communicating with AP 110. In addition, the wireless communication module 114/124 includes at least Media Address Control (MAC) layer circuitry and physical layer circuitry.

In this embodiment, the AP 110 and the station 120 are multi-link devices (MLDs), i.e., the AP 110 and the station 120 communicate with each other by using two or more links such as link-1 and link-2 shown in fig. 1. In this embodiment, link 1 may use channels corresponding to the 2.4GHz band (e.g., 2.412GHz-2.484 GHz), the 5GHz band (e.g., 4.915GHz-5.825 GHz), or the 6GHz band (e.g., 5.925GHz-7.125 GHz); and link 2 may also use channels corresponding to the 2.4GHz band, the 5GHz band, or the 6GHz band.

In this embodiment, the AP 110 and the station 120 operate in the NSTR mode, i.e., the AP 110 cannot simultaneously transmit and receive data via multiple links. As described in the context of the present invention, IEEE 802.11be defines PPDU end time alignment requirements, i.e., when multiple PPDUs are simultaneously transmitted via multiple links, respectively, their end times should be aligned with a specific tolerance requirement. Accordingly, the following embodiments provide a control method that can generate a PPDU having an appropriate length.

Fig. 2 is a control method of one of the wireless communication modules 114 and 124 according to one embodiment of the present invention. In the following description, the wireless communication module 114 is used as an example for performing the following steps, but the present invention is not limited thereto. In step 200, the flow begins and the AP 110 and station 120 have established two or more links. In step 202, the wireless communication module 114 obtains a plurality of MAC Service Data Units (MSDUs), and the wireless communication module 114 aggregates the MSDUs to generate MPDUs, wherein a MPDU may include one or more MSDUs. In step 204, the wireless communication module 114 performs Sequence Number (SN) and Packet Number (PN) assignments for each MPDU. In step 206, an encryption operation is performed on the MPDU. In step 208, MAC layer circuitry within the wireless communication module 114 performs PPDU end time alignment operations to determine symbol counts and associated settings for the PPDU. In step 208, MAC layer circuitry within wireless communication module 114 aggregates the plurality of MPDUs to generate a PPDU and transmits the PPDU to station 120 via physical layer circuitry of wireless communication module 114. Note that steps 202 to 206 and 210 are known to those skilled in the art, and the present invention focuses on PPDU end time alignment operation of step 208, so detailed operations of steps 202 to 206 and 210 are omitted here.

Fig. 3 illustrates a flowchart of a PPDU end time alignment operation according to an embodiment of the present invention. In step 302, the MAC layer circuitry of the wireless communication module 114 receives the target end time information of the PPDU and estimates a symbol count of the PPDU based on the target end time information, wherein the symbol count of the PPDU may include a data symbol count in a physical layer service data unit (PSDU) and/or SIG/LTF (signal/long training field) symbols in a preamble. In one embodiment, the target end time information includes a target length of the PPDU, and the information may be derived based on a multi-link operation (MLO) or Dual Band Dual Concurrency (DBDC) link or "TXVECTOR" parameter defined in the IEEE 802.11 specification. Note that the determination of the target end time information or the target length of the PPDU is known to those skilled in the art, and further description is omitted herein. In this embodiment, the symbol count of the PPDU may be estimated by a target length of the PPDU, a length of each symbol (orthogonal frequency division multiplexing (OFDM) symbol), a length of a preamble of the PPDU, and other parameters such as packet extension unambiguous information. For example, without limiting the invention, the data symbol count of the PPDU can be estimated by:

In equation (1), "NSYM" is a data symbol count of the PPDU, "l_length" is a target LENGTH of the PPDU, "T _SYM" is a LENGTH of each data symbol, "T _EHT-PREAMBLE" is a LENGTH of a preamble, "b _{PE-disambiguity}" is packet extension disambiguation information, and "[ ]" is a truncation operator. Note that expression (1) is provided in the IEEE 802.11be specification, and thus an operation corresponding to this expression should be understood by those skilled in the art.

In step 304, the MAC layer circuit determines a length of a Packet Extension (PE) according to a symbol count of the PPDU, a target length of the PPDU, a length of each symbol, and a length of a preamble of the PPDU. For example, without limiting the invention, the duration of the PE (T _PE) can be estimated by:

Note that expression (2) is provided in the IEEE 802.11be specification, and thus an operation corresponding to this expression should be understood by those skilled in the art.

The duration of the PE calculated in step 304 is used for nominal packet padding requested by the receiver (e.g., station 120) as defined in the IEEE 802.11 specification to provide the receiver with additional processing time to decode the received symbols. Note that T _PE calculated in step 304 may not be sufficient to meet the nominal packet stuffing requirements.

The duration of packet expansion (T _PE) obtained in step 304 is used to support modes of packet stuffing by the PE mechanism, such as a High Efficiency (HE) mode defined in IEEE 8002.11ax and an Extremely High Throughput (EHT) mode defined in IEEE 802.11 be. If the mode of operation of the wireless communication module 114 does not support packet stuffing (e.g., very high throughput (VTH)) for the PE mechanism, the duration of the packet extension may be set directly to zero.

In step 306, the MAC layer circuitry refines the alignment settings based on an alignment mechanism, which may be a force-extra-symbol (segment) mechanism, an avoidance-extra-symbol (segment) mechanism, or a best effort mechanism; and the alignment setting includes at least one of a fill factor, a duration of a packet extension, and a final symbol count of the PPDU.

Regarding the forced-extra-symbol (-fragment) mechanism, the MAC layer directly subtracts one symbol or one symbol fragment from "N _SYM" calculated by equation (1) to obtain an alignment setting. In one embodiment, referring to fig. 4, the wireless communication module 114 does not have a mode of packet stuffing through the PE mechanism, and if the data symbol count of the PPDU calculated by using equation (1) is "N _SYM", the MAC layer determines that the new data symbol count N _SYM' is equal to N _SYM -1. That is, when generating the PPDU, the content contains more invalid data on all OFDM symbols.

In another embodiment, the wireless communication module 114 has a mode of packet stuffing through a PE mechanism, and the MAC layer circuitry intentionally reduces a pre-FEC (Forward error correction) fill factor (hereinafter a-factor) so that the PPDU has more invalid data. In the IEEE 802.11 specification, the pre-FEC fill factor has four different values, the last Orthogonal Frequency Division Multiple Access (OFDMA) symbol has four segments, and the pre-FEC fill factor having a value of "1" indicates that only the first segment of the last OFDMA symbol has valid data, and the pre-FEC fill factor having a value of "2" indicates that only the first two segments of the last OFDMA symbol have valid data. The pre-FEC fill factor having a value of "3" indicates that only the first three segments of the last OFDMA symbol have valid data, and the pre-FEC fill factor having a value of "4" indicates that all four segments of the last OFDMA symbol have valid data. In detail, referring to fig. 5, assuming that the duration of the PE calculated by equation (2) (i.e., T _PE shown in fig. 5) is 8 microseconds (μs) and the nominal packet fill required by the receiver is 16 μs, the last OFDMA symbol has four segments, each segment being 4 μs long, the MAC layer circuit may initially determine that the last OFDMA symbol has an a-factor equal to "2" such that only the first two segments of the last OFDMA symbol have valid data. The last two fragments have only invalid data such that the length of the entire invalid data is equal to or greater than the nominal packet fill (i.e., the sum of the 8 μs invalid symbol fragment and the 8 μs packet extension is equal to the 16 μs nominal packet fill). The MAC layer circuitry then adjusts the initial a-factor to "1" to increase the invalid data for the segment and the final a-factor is used as an alignment setting to be provided to the subsequent module.

In the forced-extra-symbol (-fragment) mechanism described above, by intentionally adding one symbol or invalid data of one symbol fragment, the PPDU length (PPDU time) will not change much due to subsequent encoding operations. In particular, if Low Density Parity Check (LDPC) FEC is used in a subsequent encoding operation, the encoder may temporarily need to use one or more symbols or symbol fragments to improve the encoding quality during the encoding process, wherein the one or more symbols or symbol fragments are also referred to as "LDPC extra symbols or symbol fragments" in the IEEE 802.11 specification. At this point, increased invalid data for one symbol or symbol fragment may be used for the one or more symbols or symbol fragments, and the invalid data within the PPDU still meets nominal packet padding requirements (i.e., the a-factor changes from "1" to "2" in the encoding operation).

Furthermore, in the forced-extra-symbol (-fragment) mechanism, the "LDPC extra symbol" or "LDPC extra symbol fragment" is always set to true (e.g., parameter "b _extra" shown in fig. 5 is always set to "1"), even though the encoder will not use one or more symbols or symbol fragments during the subsequent encoding process. Furthermore, the preamble of a later generated PPDU will always indicate the presence of LDPC extra symbols or symbol fragments.

With respect to the avoidance-extra-symbol mechanism, the MAC layer circuitry refers to nominal packet padding requirements to determine an a-factor and intentionally adds invalid data for one or more segments to avoid introducing extra data symbols by the encoder. Taking fig. 5 as an example, after the MAC layer circuitry initially determines that the last OFDMA symbol has an a-factor equal to "1" or "2" (which is dependent on the outcome of the encoding process) such that the length of the entire invalid data is equal to or greater than the nominal packet fill, the a-factor can be used directly as an alignment setting to be provided to the subsequent module. In one embodiment, if the encoder temporarily needs to use one or more symbols or symbol fragments during encoding to improve the encoding quality, the duration of the packet expansion may be increased to meet the nominal packet padding requirements.

With respect to best effort mechanisms, the MAC layer circuitry does not intentionally adjust the a-factor according to nominal packet filling requirements, i.e., the a-factor is determined by using a lookup table defined in the IEEE 802.11 specification.

In step 308, the alignment settings are provided to subsequent modules for encoding processing and MPDU aggregation. In this embodiment, the alignment settings include the symbol count and a-factor described above, and by using the symbol count and a-factor, a byte count of one PPDU can be obtained for MPDU aggregation.

Fig. 6 is a diagram of circuitry 600 within the wireless communication module 114, wherein the circuitry 600 is configured to perform steps 200-210 and steps 302-308, according to one embodiment of the invention. As shown in fig. 6, the circuit 600 includes an aggregation module 610, a PPDU end time alignment module 620, and two transmission modules 630 and 640. The aggregation module 610 is configured to receive MPDUs corresponding to link-1 and link-2, and the aggregation module 610 transmits target end time information of two PPDUs corresponding to link-1 and link-2, respectively, to the PPDU end time alignment module 620. The PPDU end time alignment module 620 then generates an alignment setting to the aggregation module 610 for byte count determination and MPDU aggregation using the embodiments described above. Then, the aggregation module 610 generates a first PPDU, which is wirelessly transmitted by the transmission module 630 via link 1, and a second PPDU, which is wirelessly transmitted by the transmission module 640 via link 2.

Fig. 7 is a diagram of circuitry 700 within the wireless communication module 114, wherein the circuitry 700 is configured to perform steps 200-210 and steps 302-308, according to one embodiment of the invention. As shown in fig. 7, the circuit 700 includes two aggregation modules 710 and 720, at least one PPDU end time alignment module 730, and two transmission modules 740 and 750, wherein the aggregation module 710 and the transmission module 740 correspond to link 1 and the aggregation module 720 and the transmission module 750 correspond to link 2. The aggregation module 710 is configured to receive MPDUs corresponding to the link-1, and the aggregation module 710 transmits target end time information of the PPDU to the PPDU end time alignment module 730. The PPDU end time alignment module 730 then uses the above-described embodiments to generate alignment settings to the aggregation module 710 for byte count determination and MPDU aggregation. Then, the aggregation module 710 generates a first PPDU, wherein the transmission module 740 wirelessly transmits the first PPDU via the link 1. Similarly, the aggregation module 720 is configured to receive MPDUs corresponding to link-2, and the aggregation module 720 transmits target end time information of the PPDU to the PPDU end time alignment module 730. The PPDU end time alignment module 730 then uses the above-described embodiments to generate alignment settings to the aggregation module 720 for byte count determination and MPDU aggregation. The aggregation module 720 then generates a second PPDU, wherein the transmission module 750 wirelessly transmits the second PPDU via link 2.

Those skilled in the art will readily observe that numerous modifications and alterations of the apparatus and method may be made while maintaining the teachings of the present invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.

Claims (10)

1. A control method of a wireless communication module, the control method comprising:

Receiving target end time information of a physical layer protocol data unit (PPDU), and estimating a symbol count of the PPDU according to the target end time information;

determining a duration of a packet extension of the PPDU;

refining an alignment setting comprising at least one of a fill factor, a duration of the packet extension, and the symbol count of the PPDU, wherein the fill factor indicates invalid data information of the PPDU;

generating the alignment setting including a final symbol count of the PPDU and the fill factor of the PPDU; and

And aggregating a plurality of media access control protocol data units MPDUs to generate the PPDU according to the alignment setting.

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

subtracting one symbol from the symbol count of the PPDU to generate a new symbol count of the PPDU; and

The step of generating the alignment settings comprises:

the alignment setting including the new symbol count of the PPDU is generated.

3. The control method of claim 1, wherein refining the alignment setting of the PPDU comprises:

Determining the fill factor, the duration of the packet extension, and the final symbol count of the PPDU to meet a nominal packet padding requirement and a target end time requirement of a receiver;

directly adjusting the fill factor so that the PPDU has more invalid data; and

The step of generating the alignment settings comprises:

The alignment settings including the final symbol count of the PPDU, a new packet extension duration, and a new fill factor of the PPDU are generated.

4. A control method according to claim 3, wherein the fill factor is a pre-FEC forward error correction fill factor, the last symbol of the PPDU comprises a plurality of segments, and the step of directly adjusting the fill factor such that the PPDU has more invalid data comprises:

the fill factor is directly adjusted so that the last symbol has at least one more segment with invalid data.

5. The control method of claim 1, wherein refining the alignment setting of the PPDU comprises:

Determining the fill factor, the duration of the packet extension, and the final symbol count of the PPDU to meet a nominal packet padding requirement and a target end time requirement of a receiver;

wherein the fill factor, the duration of the packet extension, and the final symbol count are directly used as part of the alignment setting.

6. A circuit of a wireless communication module, the circuit configured to perform the steps of:

Receiving target end time information of a physical layer protocol data unit (PPDU), and estimating a symbol count of the PPDU according to the target end time information;

determining a duration of a packet extension of the PPDU;

refining an alignment setting comprising at least one of a fill factor, a duration of the packet extension, and the symbol count of the PPDU, wherein the fill factor indicates invalid data information of the PPDU;

generating the alignment setting including a final symbol count of the PPDU and the fill factor of the PPDU; and

And aggregating a plurality of media access control protocol data units MPDUs to generate the PPDU according to the alignment setting.

7. The circuit of claim 6, the circuit further comprising:

subtracting one symbol from the symbol count of the PPDU to generate a new symbol count of the PPDU; and

The step of generating the alignment settings comprises:

the alignment setting including the new symbol count of the PPDU is generated.

8. The circuit of claim 6, wherein refining the alignment setting of the PPDU comprises:

Determining the fill factor, the duration of the packet extension, and the final symbol count of the PPDU to meet a nominal packet padding requirement and a target end time requirement of a receiver;

directly adjusting the fill factor so that the PPDU has more invalid data; and

The step of generating the alignment settings comprises:

The alignment settings including the final symbol count of the PPDU, a new packet extension duration, and a new fill factor of the PPDU are generated.

9. The circuit of claim 8, wherein the fill factor is a pre-FEC forward error correction fill factor, a last symbol of a PPDU comprises a plurality of segments, and the step of directly adjusting the fill factor such that the PPDU has more invalid data comprises:

the fill factor is directly adjusted so that the last symbol has at least one more segment with invalid data.

10. The circuit of claim 6, wherein refining the alignment setting of the PPDU comprises:

Determining the fill factor, the duration of the packet extension, and the final symbol count of the PPDU to meet a nominal packet padding requirement and a target end time requirement of a receiver;

wherein the fill factor, the duration of the packet extension, and the final symbol count are directly used as part of the alignment setting.