Multi-user power control method and procedure

Abstract

Methods and systems for operating in a WLAN are provided. Methods and systems for transmit power control (TPC) schemes are disclosed. In one embodiment, an access point (AP) can send a trigger frame to one or more stations (STAs) for synchronization and scheduling of uplink (UL) multi-user (MU) transmissions. The trigger frame can contain an open loop power control index 1 and a power adjustment index 2. The one or more STAs can use the indicated AP transmit power and receive power to estimate path loss to set a baseline power. The one or more STAs can adjust their transmit power to the target receive power indicated at the AP in the UL transmission period.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201680051814.5, filed on September 9, 2016, entitled "Multi-user Power Control Method and Process", the contents of which are incorporated herein by reference.

[0002] Cross-reference to related applications

[0003] This application claims the benefit of U.S. Provisional Application No. 62 / 216,666, filed September 10, 2015, and U.S. Provisional Application No. 62 / 245,325, filed October 23, 2015, the entire contents of which are incorporated herein by reference. Background Technology

[0004] A Wireless Local Area Network (WLAN) is a wireless computer network that uses a wireless distributed method (typically spread spectrum or OFDM radio) to link two or more devices within a limited area such as a home, school, computer lab, or office building. This gives users the ability to move around within a local coverage area while still remaining connected to the network. WLANs can also provide connectivity to the wider Internet. Most modern WLANs are based on the IEEE 802.11 standard. Summary of the Invention

[0005] The following description includes methods, systems, and apparatus for performing transmit power control (TPC) procedures in a wireless local area network (WLAN). Implementations include: receiving a trigger frame from an access point (AP) via a station (STA), the trigger frame indicating that the STA is a candidate for an upcoming uplink (UL) multi-user (MU) transmission opportunity, the trigger frame including a first index indicating open-loop power control parameters and a second index indicating power calibration parameters; determining a baseline transmit power via the STA based on one or more of the trigger frame, the first index, and the second index; and transmitting data to the AP via the STA using the baseline transmit power in one or more assigned resource units of the ULMU transmission opportunity.

[0006] Furthermore, the implementation includes a station (STA) for performing a transmit power control (TPC) procedure. The STA may include: at least one receiving circuit configured to receive a trigger frame from an access point (AP) indicating that the STA is a candidate for an upcoming uplink (UL) multi-user (MU) transmission opportunity, the trigger frame including a first index indicating open-loop power control parameters and a second index indicating power calibration parameters; at least one processor configured to determine a baseline transmit power based on one or more of the trigger frame, the first index, and the second index; and at least one transmitting circuit configured to transmit data to the AP using the baseline transmit power in one or more assigned resource units of the ULMU transmission opportunity.

[0007] The implementation may further include: receiving downlink (DL) data transmission from an access point (AP) via a station (STA), wherein the header of the DL data transmission includes a first index indicating open-loop power control parameters and a second index indicating power calibration parameters; determining a baseline transmit power via the STA based on one or more of the first index and the second index; and transmitting uplink (UL) data transmission to the AP via the STA using the baseline transmit power. Attached Figure Description

[0008] A more detailed understanding can be obtained from the following description, which is given in conjunction with the accompanying drawings and examples, wherein:

[0009] Figure 1A This is a system illustration of an example communication system in which one or more of the disclosed embodiments may be implemented;

[0010] Figure 1B It is possible Figure 1A A system diagram illustrating an example wireless transmit / receive unit (WTRU) used within a communication system is shown.

[0011] Figure 1C It is possible Figure 1A The system diagram shows an example radio access network and an example core network used within the communication system;

[0012] Figure 2 The following is an example of the sub-1GHz (S1G) open-loop link margin index element as defined in IEEE 802.11ah;

[0013] Figure 3 The preliminary trigger frame format proposed for IEEE 802.11 is shown;

[0014] Figure 4 It is a frequency domain representation of image distortion;

[0015] Figure 5 This is an illustration of the transmission frames exchanged during an exemplary transmit power control (TPC) procedure for random access;

[0016] Figure 6 This is a diagram illustrating the steps of an exemplary TPC procedure for random access;

[0017] Figure 7 This is a network diagram illustrating the transmit power control (TPC) information carried in the DL trigger frame, which allows the station (STA) to set the transmit power accordingly in the subsequent UL random access transmission;

[0018] Figure 8 This illustrates random access with limitations derived from the received power range;

[0019] Figure 9 The TPC for uplink (UL) data is shown;

[0020] Figure 10 The TPC for a UL control frame including a UL response (ACK) is shown;

[0021] Figure 11 The TPC for a UL control frame including UL Clear Transmission (CTS) is shown;

[0022] Figure 12 TPC is shown for cascaded UL and downlink (DL) transmissions; and

[0023] Figure 13 The TPC process with cascading transmission opportunities is shown. Detailed Implementation

[0024] Figure 1A This is a system illustration of an example communication system 100 in which one or more of the disclosed embodiments may be implemented. The communication system 100 may be a multi-access system that provides content such as voice, data, video, message transmission, broadcasting, etc., to multiple wireless users. The communication system 100 enables multiple wireless users to access this content through the sharing of system resources (including wireless bandwidth). For example, the communication system 100 may use one or more channel access methods, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), etc.

[0025] like Figure 1AAs shown, the communication system 100 may include wireless transmit / receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112. However, it should be understood that the disclosed embodiments cover any number of WTRUs, base stations, networks, and / or network elements. Each of the WTRUs 102a, 102b, 102c, and 102d can be any type of device configured to operate and / or communicate in a wireless environment. As an example, the WTRUs 102a, 102b, 102c, and 102d may be configured to transmit and / or receive wireless signals and may include user equipment (UE), mobile stations, fixed or mobile subscriber units, pagers, cellular phones, personal digital assistants (PDAs), smartphones, laptops, netbooks, personal computers, wireless sensors, consumer electronics, and so on.

[0026] The communication system 100 may also include base stations 114a and 114b. Each of base stations 114a and 114b may be any type of device configured to wirelessly interface with at least one of WTRUs 102a, 102b, 102c, and 102d to facilitate access to one or more communication networks (e.g., core network 106, Internet 110, and / or network 112). For example, base stations 114a and 114b may be base transceiver stations (BTS), node B, e-node B, home node B, home e-node B, site controllers, access points (APs), wireless routers, etc. Although each of base stations 114a and 114b is described as a single element, it is to be understood that base stations 114a and 114b may include any number of interconnected base stations and / or network elements.

[0027] Base station 114a may be part of RAN 104, which may also include other base station and / or network elements (not shown), such as base station controller (BSC), radio network controller (RNC), and relay nodes. Base station 114a and / or base station 114b may be configured to transmit and / or receive radio signals within a specific geographic area, which may be referred to as a cell (not shown). The cell may also be divided into cell sectors. For example, the cell associated with base station 114a may be divided into three sectors. Thus, in one embodiment, base station 114a may include three transceivers, i.e., one transceiver for each sector of the cell. In another embodiment, base station 114a may use multiple-input multiple-output (MIMO) technology and therefore may use multiple transceivers for each sector of the cell.

[0028] Base stations 114a and 114b can communicate with one or more of WTRUs 102a, 102b, 102c, and 102d via air interface 116, which can be any suitable wireless communication link (e.g., radio frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Air interface 116 can be established using any suitable radio access technology (RAT).

[0029] More specifically, as described above, the communication system 100 can be a multi-access system and can use one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, etc. For example, base stations 114a and WTRUs 102a, 102b, and 102c in RAN 104 can implement radio technologies such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which can use Wideband CDMA (WCDMA) to establish the air interface 116. WCDMA can include communication protocols such as High-Speed ​​Packet Access (HSPA) and / or Evolved HSPA (HSPA+). HSPA can include High-Speed ​​Downlink Packet Access (HSDPA) and / or High-Speed ​​Uplink Packet Access (HSUPA).

[0030] In another implementation, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may use Long Term Evolution (LTE) and / or LTE-Advanced (LTE-A) to establish air interface 116.

[0031] In other implementations, base station 114a and WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.16 (i.e., Global Microwave Interconnection Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Provisional Standard 2000 (IS-2000), Provisional Standard 95 (IS-95), Provisional Standard 856 (IS-856), Global System for Mobile Communications (GSM), Enhanced Data Rate GSM Evolution (EDGE), and GSM EDGE (GERAN).

[0032] Figure 1ABase station 114b can be, for example, a wireless router, a home node B, a home e-node B, or an access point, and can use any suitable RAT to facilitate wireless connectivity in localized areas such as commercial areas, homes, vehicles, and campuses. In one embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.11 to establish a wireless local area network (WLAN). In another embodiment, base station 114b and WTRUs 102c, 102d can implement radio technologies such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, base station 114b and WTRUs 102c, 102d can use cellular-based RATs (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish picocells or femtocells. Figure 1A As shown, base station 114b can have a direct connection to the Internet 110. Therefore, base station 114b does not need to go through core network 106 to access the Internet 110.

[0033] RAN 104 can communicate with core network 106, which can be any type of network configured to provide voice, data, application, and / or Voice over Internet Protocol (VoIP) services to one or more of WTRUs 102a, 102b, 102c, and 102d. For example, core network 106 can provide call control, billing services, location-based services, prepaid calling, internet connectivity, video distribution, and / or perform advanced security functions such as user authentication. Although Figure 1A Although not shown, it should be understood that RAN 104 and / or core network 106 can communicate directly or indirectly with other RANs that use the same RAT as RAN 104 or a different RAT. For example, in addition to connecting to RAN 104, which can use E-UTRA radio technology, core network 106 can also communicate with RANs (not shown) that use GSM radio technology.

[0034] Core network 106 can also serve as a gateway for WTRUs 102a, 102b, 102c, and 102d to access PSTN 108, the Internet 110, and / or other networks 112. PSTN 108 may include a circuit-switched telephone network providing Common Old-Style Telephone Service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices using common communication protocols, such as Transmission Control Protocol (TCP), User Datagram Protocol (UDP), and Internet Protocol (IP) from the Internet Protocol Suite. Network 112 may include wireless or wired communication networks owned and / or operated by other service providers. For example, network 112 may include a core network connected to one or more RANs, which may use the same RAT as RAN 104 or a different RAT.

[0035] Some or all of the WTRUs 102a, 102b, 102c, and 102d in the communication system 100 may include multi-mode capability; that is, WTRUs 102a, 102b, 102c, and 102d may include multiple transceivers for communicating with different wireless networks via different wireless links. For example, Figure 1A The WTRU 102c shown can be configured to communicate with base station 114a, which can use cellular-based radio technology, and with base station 114b, which can use IEEE 802 radio technology.

[0036] Figure 1B This is a system diagram of example WTRU 102. (Example:) Figure 1B As shown, WTRU 102 may include a processor 118, a transceiver 120, a transmitting / receiving element 122, a speaker / microphone 124, a keyboard 126, a display / touchpad 128, non-removable memory 130, removable memory 132, a power supply 134, a Global Positioning System (GPS) chipset 136, and other peripheral devices 138. It should be understood that, while remaining consistent with the implementation, WTRU 102 may include any sub-combination of the above-described elements.

[0037] Processor 118 may be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, etc. Processor 118 may perform signal encoding, data processing, power control, input / output processing, and / or any other function that enables WTRU 102 to operate in a wireless environment. Processor 118 may be coupled to transceiver 120, which may be coupled to transmitting / receiving element 122. Although... Figure 1B The processor 118 and transceiver 120 are described as separate components, but the processor 118 and transceiver 120 can be integrated together into an electronic package or chip.

[0038] Transmitting / receiving element 122 can be configured to transmit signals to or receive signals from a base station (e.g., base station 114a) via air interface 116. For example, in one embodiment, transmitting / receiving element 122 can be an antenna configured to transmit and / or receive RF signals. For example, in another embodiment, transmitting / receiving element 122 can be a transmitter / detector configured to transmit and / or receive, for example, IR, UV, or visible light signals. In yet another embodiment, transmitting / receiving element 122 can be configured to transmit and receive both RF signals and optical signals. It should be understood that transmitting / receiving element 122 can be configured to transmit and / or receive any combination of wireless signals.

[0039] Furthermore, although the transmitting / receiving element 122 is in Figure 1B While described as a single element, WTRU 102 may include any number of transmitting / receiving elements 122. More specifically, WTRU 102 may use MIMO technology. Thus, in one embodiment, WTRU 102 may include two or more transmitting / receiving elements 122 (e.g., multiple antennas) for transmitting and / or receiving wireless signals via air interface 116.

[0040] Transceiver 120 can be configured to modulate signals to be transmitted by transmitting / receiving element 122 and to demodulate signals received by transmitting / receiving element 122. As described above, WTRU 102 can have multi-mode capability. Thus, transceiver 120 can include multiple transceivers to enable WTRU 102 to communicate via multiple RATs, such as UTRA and IEEE 802.11.

[0041] The processor 118 of WTRU 102 can be coupled to a speaker / microphone 124, a keyboard 126, and / or a display / touchpad 128 (e.g., a liquid crystal display (LCD) unit or an organic light-emitting diode (OLED) display unit), and can receive user input data from the aforementioned devices. The processor 118 can also output user data to the speaker / microphone 124, keyboard 126, and / or display / touchpad 128. Furthermore, the processor 118 can access information from any type of suitable memory, and store data in any type of suitable memory, such as non-removable memory 130 and / or removable memory 132. Non-removable memory 130 can include random access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. Removable memory 132 can include a subscriber identification module (SIM) card, a memory stick, a secure digital storage (SD) card, etc. In other embodiments, processor 118 may access data from memory that is not physically located on WTRU 102 (e.g., on a server or home computer (not shown)) and store data in such memory.

[0042] The processor 118 can receive electrical energy from the power supply 134 and can be configured to distribute that electrical energy to other components in the WTRU 102 and / or control the electrical energy to other components in the WTRU 102. The power supply 134 can be any device suitable for powering the WTRU 102. For example, the power supply 134 may include one or more dry cell batteries (NiCd, NiZn, NiMH, Li-ion, etc.), solar cells, fuel cells, etc.

[0043] The processor 118 may also be coupled to a GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) about the current location of the WTRU 102. As a supplement to or alternative to the information from the GPS chipset 136, the WTRU 102 may receive location information from base stations (e.g., base stations 114a, 114b) via the air interface 116, and / or determine its location based on the timing of signals received from two or more adjacent base stations. It should be understood that, while remaining consistent with the implementation, the WTRU 102 may acquire location information using any suitable location determination method.

[0044] The processor 118 can also be coupled to other peripheral devices 138, which may include one or more software and / or hardware modules providing additional features, functions, and / or wireless or wired connectivity. For example, peripheral devices 138 may include an accelerometer, an electronic compass (e-compass), a satellite transceiver, a digital camera (for photos or videos), a Universal Serial Bus (USB) port, a vibration device, a television transceiver, a hands-free headset, etc. Modules, FM radio units, digital music players, media players, video game console modules, internet browsers, etc.

[0045] Figure 1C This is an example system diagram of RAN 104 and core network 106 according to one embodiment. As described above, RAN 104 can communicate with WTRUs 102a, 102b, and 102c via air interface 116 using E-UTRA radio technology. RAN 104 can also communicate with core network 106.

[0046] RAN 104 may include eNodeBs 140a, 140b, and 140c, but it should be understood that RAN 104 may include any number of eNodeBs while maintaining consistency with the implementation. Each of eNodeBs 140a, 140b, and 140c may include one or more transceivers for communicating with WTRUs 102a, 102b, and 102c via air interface 116. In one implementation, eNodeBs 140a, 140b, and 140c may implement MIMO technology. Therefore, eNodeB 140a may, for example, use multiple antennas to transmit and receive radio signals from WTRU 102a.

[0047] Each of eNodeB 140a, 140b, and 140c can be associated with a specific cell (not shown) and can be configured to handle radio resource management decisions, handover decisions, and scheduling of users in the uplink and / or downlink, etc. Figure 1C As shown, nodes B140a, 140b, and 140c can communicate with each other via the X2 interface.

[0048] Figure 1C The core network 106 shown may include a Mobility Management Entity Gateway (MME) 142, a Serving Gateway 144, and a Packet Data Network (PDN) Gateway 146. Although each of the foregoing elements is described as part of the core network 106, it should be understood that any of these elements may be owned and / or operated by an entity other than the core network operator.

[0049] MME 142 can connect to each of the eNodeBs 140a, 140b, and 140c in RAN 104 via the S1 interface and can act as a control node. For example, MME 142 can be responsible for authenticating users of WTRUs 102a, 102b, and 102c, bearer activation / deactivation, selecting a specific serving gateway during the initial attachment of WTRUs 102a, 102b, and 102c, etc. MME 142 can also provide control plane functions for handover between RAN 104 and other RANs (not shown) employing other radio technologies such as GSM or WCDMA.

[0050] Service gateway 144 can connect to each of eNodeBs 140a, 140b, and 140c in RAN 104 via the S1 interface. Service gateway 144 typically routes and forwards user data packets to / from WTRUs 102a, 102b, and 102c. Service gateway 144 can also perform other functions, such as anchoring the user plane during handover between eNodeBs, triggering paging when downlink data is available to WTRUs 102a, 102b, and 102c, and managing and storing the context of WTRUs 102a, 102b, and 102c.

[0051] Service gateway 144 can also be connected to PDN gateway 146, which can provide WTRU 102a, 102b, 102c with access to a packet-switched network such as the Internet 110, so as to facilitate communication between WTRU 102a, 102b, 102c and IP-enabled devices.

[0052] Core network 106 facilitates communication with other networks. For example, core network 106 can provide WTRUs 102a, 102b, and 102c with access to a circuit-switched network such as PSTN 108, facilitating communication between WTRUs 102a, 102b, and 102c and traditional landline communication equipment. For instance, core network 106 may include or communicate with an IP gateway (e.g., an IP Multimedia Subsystem (IMS) server) serving as an interface between core network 106 and PSTN 108. Furthermore, core network 106 can provide WTRUs 102a, 102b, and 102c with access to network 112, which may include other wired or wireless networks owned and / or operated by other service providers.

[0053] Other networks 112 can also connect to an IEEE 802.11-based wireless local area network (WLAN) 160. WLAN 160 may include an access router 165. The access router may include gateway functionality. Access router 165 can communicate with multiple access points (APs) 170a and 170b. Communication between access router 165 and APs 170a and 170b can be via wired Ethernet (IEEE 802.3 standard) or any type of wireless communication protocol. AP 170a communicates with WTRU 102 via an air interface.

[0054] A WLAN in Infrastructure Basic Services Set (BSS) mode can have an Access Point (AP) for the BSS and one or more Stations (STAs) associated with that AP. The AP typically has access or an interface to another type of wired / wireless network or Distributed System (DS) carrying traffic to and from the BSS. Traffic originating outside the BSS to a STA can pass through the AP and be delivered to the STA. Traffic originating from a STA to a destination outside the BSS can be sent to the AP for delivery to the respective destination. Traffic between STAs within the BSS can also be sent through the AP, where the source STA sends traffic to the AP, and the AP delivers traffic to the destination STA. Such traffic between STAs within the BSS can be end-to-end traffic. Such end-to-end traffic can also be sent directly between source and destination STAs using DLS employing IEEE 802.11e DLS or IEEE 802.11z Tunneled Direct Link Establishment (DLS) (TDLS). A WLAN using Standalone BSS (IBSS) mode does not have APs and / or STAs communicating directly with each other. This communication mode is called an "ad-hoc" communication mode.

[0055] Using the IEEE 802.11ac infrastructure operating mode, the AP 170a can transmit beacons on a fixed channel (typically the primary channel). This channel can be 20 MHz wide and can be the operating channel of the BSS. This channel can also be used by one or more stations (STAs) to establish connections with the AP 170a. The basic channel access mechanism in the IEEE 802.11 system can be Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). In this operating mode, each STA, including the AP 170a, can sense the primary channel. If the channel is detected as busy, the STA can back off. Therefore, only one STA can transmit in a given BSS at any given time.

[0056] In IEEE 802.11n, high-throughput (HT) STAs can also use a 40MHz wide channel for communication. This can be achieved by combining a primary 20MHz channel with an adjacent 20MHz channel to form a continuous 40MHz wide channel.

[0057] In IEEE 802.11ac, Very High Throughput (VHT) STAs can support channels with widths of 20MHz, 40MHz, 80MHz, and 160MHz. 40MHz and 80MHz channels can be formed by combining consecutive 20MHz channels, similar to the IEEE 802.11n specification described above. A 160MHz channel can be formed by combining eight consecutive 20MHz channels, or by combining two non-consecutive 80MHz channels (which can be referred to as an 80+80 configuration). For the 80+80 configuration, after channel coding, the data passes through a segment resolver, which divides the data into two streams. Each stream can then undergo Inverse Fast Fourier Transform (IFFT) and time-domain processing. The streams can then be mapped to the two channels, and the data can be transmitted. At the receiver, this mechanism can be reversed, and the combined data can be sent to the MAC.

[0058] The sub-1 GHz operating mode can be supported by IEEE 802.11af and IEEE 802.11ah. For these specifications, the channel operating bandwidth and carrier can be reduced compared to those used in IEEE 802.11n and IEEE 802.11ac. The IEEE 802.11af specification can support bandwidths of 5 MHz, 10 MHz, and 20 MHz in the TV white space (TVWS) spectrum. The IEEE 802.11ah specification can support bandwidths of 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz using non-TVWS spectrum. Possible use cases for IEEE 802.11ah include supporting instrument-type control (MTC) devices in macro coverage areas. MTC devices can have limited capabilities, including supporting only limited bandwidth, but can also include requirements for long battery life.

[0059] WLAN systems supporting multiple channels and channel bandwidths, such as IEEE 802.11n, IEEE 802.11ac, IEEE 802.11af, and IEEE 802.11ah, may include a channel designated as the primary channel. This primary channel may, but is not required to, have a bandwidth equal to the maximum common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel is therefore limited by the STAs in the BSS that support the minimum bandwidth operating mode. In the example of IEEE 802.11ah, if there are STAs that only support the 1MHz mode (e.g., MTC type devices), the primary channel can be 1MHz wide, even if the AP and other STAs in the BSS support 2MHz, 4MHz, 8MHz, 16MHz, or other channel bandwidth operating modes. All carrier sense and NAV settings can depend on the status of the primary channel. For example, if the primary channel is busy (e.g., because the STA only supports the 1MHz operating mode to transmit to the AP), the entire available band can be considered busy, even if most of it is idle and available.

[0060] In the United States, the available frequency bands for IEEE 802.11ah range from 902MHz to 928MHz. In South Korea, the available frequency bands range from 917.5MHz to 923.5MHz. In Japan, the available frequency bands range from 916.5MHz to 927.5MHz. The total bandwidth available for IEEE 802.11ah can range from 6MHz to 26MHz depending on the country code.

[0061] In wireless networks, transmit power control (TPC) can be used for a variety of reasons, including minimizing interference between nodes, improving wireless link quality, reducing power consumption, controlling topology, reducing interference with satellites / radar in 5GHz mode, and improving coverage in the network.

[0062] Existing cellular standards can have different approaches to implementing TPC. Here, a conventional approach for TPC that can be used in Wideband Code Division Multiple Access (WCDMA) / High-Speed ​​Packet Access (HSPA) is further disclosed. In WCDMA and HSPA, TPC can be a combination of open-loop power control, outer-loop power control, and inner-loop power control. This ensures that the power at the receiver in the uplink is equal for all WTRUs associated with the Node B or base station. This can be important due to the near-far problem caused by CDMA multiple access schemes. Since all WTRUs utilize the entire spectrum, if the transmit power of different WTRUs is not managed, the receive power of STAs far from the base station can be suppressed by those closer to the base station.

[0063] In open-loop power control between the WTRU and the Radio Network Controller (RNC), each WTRU transmitter can set its output power to a specific value to compensate for path loss. This power control scheme can set the initial uplink and downlink transmission power when the WTRU is accessing the network.

[0064] In the outer-loop power control, which also occurs between the WTRU and RNC, long-term channel variations can be compensated for. This power control scheme can be used to maintain communication quality at the level required for the bearer's quality of service while using the lowest possible power. The uplink outer-loop power control is responsible for setting the target signal-to-interference ratio (SIR) in the Node B for each individual uplink inner-loop power control. The target SIR can be updated for each WTRU based on the block error rate (BLER) or bit error rate (BER) of each RRC connection at frequencies between 10 Hz and 100 Hz. The downlink outer-loop power control allows the WTRU to converge to the required link quality (BLER) set by the downlink network (RNC).

[0065] In inner-loop power control (i.e., fast closed-loop power control) that can occur between the WTRU and Node B, each WTRU can compensate for short-term channel variations. In the uplink, the WTRU can, for example, adjust its output power at 1500 Hz based on one or more TPC commands received from the downlink signal from the base station. This maintains the received uplink SIR at the desired SIR target.

[0066] Conventional methods for TPC that can be used in uplink Universal Mobile Telecommunications System (UMTS) Long Term Evolution (LTE) are disclosed herein. In uplink LTE, power control can be a combination of basic open-loop TPC, dynamic closed-loop TPC, and bandwidth factor compensation components. The effective transmit power can be calculated as:

[0067] Tx power =P0+αPL+Δ TF +f(Δ TPC )+10log 10 Equation (1) of M

[0068] LTE can use single-carrier frequency division multiple access (SC-FDMA) in the uplink, so the need for tight power control is not as critical as in WCDMA / HSPA.

[0069] The basic open-loop TPC can achieve partial power control, where the WTRU can compensate for a portion of the path losses, and can be calculated as follows:

[0070] Txpoweer =P0+αPL Equation (2)

[0071] Here, α can be a partial path loss compensation parameter. Parameter P0 can be a WTRU-specific offset component that enables the eNodeB to correct for the system offset in the WTRU's transmit power. The PL parameter can be an estimate of the path loss for the WTRU derived from the Received Signal Received Power (RSRP) and the eNodeB transmit power. The partial path loss compensation factor α can balance the fairness of cell capacity. It is typically set between 0.7 and 0.8 and can reduce the impact of cell edge transmission, thereby increasing system capacity while minimizing the impact on cell edge performance. It can be used on the Physical Uplink Shared Channel (PUSCH). The Physical Uplink Control Channel (PUCCH) can have α = 1 and can have different P0 values.

[0072] Closed-loop power control is dynamic and can perform a hybrid of interference control and channel condition adaptation. Closed-loop power control can use terms;

[0073] Δ TF +f(Δ TPC Equation (3)

[0074] Parameter Δ TF These can be parameters related to the modulation and coding scheme (MCS) based on Shannon's capacity theorem. WTRU-specific parameter f(Δ) TPC It can be similar to the closed-loop TPC term in WCDMA / HSPA, and its power can be increased or decreased based on the power indication received at the eNB by the WTRU.

[0075] The bandwidth factor is a factor of 10log that scales the transmit power based on the actual number of scheduled RBs. 10 M.

[0076] The TPC requirements for WLAN differ from those of cellular systems for several reasons. In CDMA, two WTRUs (Root Transceiver Units) near the Base Transceiver Station (BTA) and far from the BTA can transmit simultaneously. This can create a "near-far problem." For WLAN, being a time-domain system, only one STA (Station) is transmitting within the BSS at any given time. Thus, tight closed-loop power control may not be essential. Unlike LTE, where a central scheduler controls multiple access algorithms, the primary multiple access algorithm in 802.11 WLAN can be distributed across Distributed Coordination Function (DCF) or Enhanced Distributed Channel Access (EDCA) multiple access methods. Therefore, the need to balance the fairness of uplink scheduling of cell-edge WTRUs to overall cell capacity is less stringent, and explicit partial path loss compensation may be less critical. Furthermore, Orthogonal Frequency Domain Multiple Access (OFDMA) may not exist, and each STA / AP can occupy the entire bandwidth. Thus, there may be no need for a bandwidth factor. The main part of the IEEE 802.11 standard emphasizes algorithmic simplicity, with receivers providing TPC recommendations and each transmitter determining its specific transmit power based on the manufacturer's own implementation concerns and management requirements.

[0077] Therefore, WLAN systems can specify different types of TPC procedures relative to cellular-based TPC procedures. The standard TPC procedures in the IEEE 802.11 WLAN specification can support one or more of the following features: STA-AP association based on STA power capacity; mesh STA peering based on mesh STA power capacity; specification of current channel policing and local maximum transmit power levels; selection of transmit power for each transmission in the channel within constraints imposed by policing and local requirements; and adaptive transmit power based on several information elements (IEs), including path loss and link margin estimation.

[0078] The implementations disclosed herein may include directional multi-gigabit WLAN transmissions using directional millimeter-wave transmissions as specified in IEEE 802.11ad. Hereinafter, WLAN transmissions governed by all other specifications including IEEE 802.11-2012, IEEE 802.11ac, IEEE 802.11af, and IEEE 802.11ah may be defined as non-directional IEEE 802.11 WLAN transmissions.

[0079] In non-directional IEEE 802.11 WLAN transmissions, the receiving STA can send a TPC report element that includes transmit power and link margin. Link margin can be defined as the ratio of the received power to the power required for the STA to shut down the link. The transmitter can use the information received in the TPC report to determine the transmit power. STAs can use any criteria to dynamically adapt their transmit power to another STA based on information received from other STAs via feedback. Specific methods may vary depending on the implementation. This can be described as open-loop TPC. Open-loop TPC implies that the transmitter, whether at the AP or a non-STA, can determine the transmit power independently of the STA's process.

[0080] TPC reports can be requested by the receiver, with explicit TPC request frames sent by the transmitter. Alternatively, TPC reports can be unsolicited by, for example, an AP in a BSS or a STA in an IBSS.

[0081] Using directional multi-gigabit IEEE 802.11 WLAN transmission modes, such as IEEE 802.11ad, the directional multi-gigabit (DMG) link margin element can include a field recommending an increase or decrease in transmit power. In this case, the transmitter can send a DMG link adaptive response to indicate whether it will implement the recommendation.

[0082] Now refer to Figure 2 The IEEE 802.11ah specification discloses open-loop link margins. The IEEE 802.11ah specification has introduced sub-1GHz (S1G) open-loop link margin indices for open-loop link adaptation and power control. Figure 2 It is an S1G open-loop link margin index element format 200, which can contain element ID 202, length 204 and open-loop margin index 206.

[0083] Open-loop link margin Δ OPLM It can be defined as the transmit power P tx and receiver sensitivity RX sensitivity (RX 灵敏度 The sum of ), and can be defined as follows:

[0084] Δ OPLM =P tx +RX sensitivity Equation (4)

[0085] Receiver sensitivity RX sensitivity This can be the minimum required receive power for an MCS 10 channel at 1MHz. The open-loop link margin Δ OPLM It can be calculated as (-128+D×0.5)dB, where D can be the open-loop link margin index 206.

[0086] S1G open-loop link margin index 206 can be used for open-loop link adaptation and open-loop transmit power control. When the STA receives open-loop link margin index 206, it can calculate the S1G open-loop link margin Δ using (-128 + D × 0.5) dB. OPLM The SNR margin on MCS 10 can be derived by the STA receiving a frame containing the S1G open-loop link margin index 206. This can be based on the STA's own transmit power P. tx2 And the Received Signal Strength Indicator (RSSI) for packet measurements including S1G open-loop link margin index 206:

[0087] SNR margin =P tx2 -Δ OPLM +RSSI Equation (5)

[0088] Developments in multi-user (MU) transport and power control are disclosed here. The IEEE Standards Committee has endorsed the IEEE 802.11ax Task Group (TGax) based on the Standards Development Guidelines (CSD) and Request for Project Authorization (PAR) developed within the High Efficiency WLAN Study Group (HEW SG). MU transport, including both downlink and uplink transport, has been included in the TGax Specification Framework Document (SFD).

[0089] Now for reference Figure 3 An example of the trigger frame format is shown. The trigger frame may not include power control information in the public information field. It has been proposed that the per-user information field of the trigger frame may include power control information, but the details of this implementation have not yet been determined. The trigger frame may also support the allocation of resource units for random access. The trigger frame for random access may be referred to as TF-R, and the proposed random access is similar to slotted Aloha. However, power control has not been disclosed.

[0090] Conventional techniques may include one or more of the following methods: multi-level power control and association processes, partially compensated power control and association processes, continuous closed-loop power control and association processes, enabling multi-level power control in a transmit-receive session, modification of the idle channel assessment (CCA) threshold for energy detection, coverage adjustment in interference-limited networks, transmit power control and association processes for multiple channels / users, transmit power control and association processes for multi-AP transmission, and power level initialization and association processes when waking up from power-saving mode.

[0091] In addition, conventional techniques may include one or more of the following methods: CCA adaptation with or without transmit power control, utility function-based transmit power control with CCA adaptation, normalized transmit power control with CCA adaptation, MCS-dependent TPC / CCA adaptation, and BSS-wide TPC / CCA adaptation.

[0092] The implementation described herein can solve one or more problems. One problem may relate to power control of uplink (UL)MU transmissions. Concurrent ULMU transmissions may require uplink power control. Without power control, the receive power at the AP for multiple concurrent uplink STAs can be substantially altered. This can cause reception problems at the AP, including automatic gain control, IQ imbalance, frequency offset, and cascaded transmissions.

[0093] Regarding Automatic Gain Control (AGC), the AP must maintain the total received power from multiple STAs within the dynamic range of the AP's receiver front end. Without regulations controlling the transmitted power of the STAs, the dynamic range of the received power at the AP can exceed the capabilities of the receiver front end.

[0094] Amplitude and phase imbalances in the in-phase and quadrature (I / Q) components of a signal transmitted on a subchannel can cause interference in the mirror image of that subchannel. The severity of distortion depends on the level of I / Q amplitude and phase imbalance. Figure 4 The frequency domain representation of image distortion is shown.

[0095] Due to orthogonality loss, frequency offsets between signals transmitted on adjacent sub-channels can cause interference. The interference level can be further aggravated by the power difference between signals on adjacent sub-channels.

[0096] Cascaded transmission refers to the dependency of the most recent state from UL transmission to DL transmission. UL power control using this scheme can rely on information received from the DL transmission.

[0097] There may be issues associated with existing power control mechanisms defined in the IEEE 802.11 specification. For example, existing TPC procedures may be high-level (semi-static) and function normally, such as in beacon frames or association request / response frames. Therefore, TPC information may not be updated frequently. However, received power, which can be a function of, for example, the physical channel and / or transmission bandwidth, can change rapidly. Outdated TPC information may not provide sufficiently accurate power control.

[0098] Another issue could be power control for high-bandwidth transmissions. In high-bandwidth transmissions, different bands may require different TPC adjustment levels. Methods and processes are needed to determine whether different TPC adjustment levels are required, and (a) to obtain the TPC level and (b) to send the TPC level to the STA.

[0099] Another issue could be power control calibration. When using open-loop TPC, the AP may need to calibrate the STA response to the desired TP level. This can lead to undesirable closed-loop behavior, where the AP instructs the STA to make changes based on AP requirements.

[0100] Another issue is transmit power control for fast-moving STAs. In IEEE 802.11n and IEEE 802.11ac, the use of TPC reports does not consider the receiver's Rx sensitivity. The open-loop link margin proposed in IEEE 802.11ah addresses this issue, but assumes a fixed, low duty cycle transmitter. Therefore, the regular use of open-loop link margin indexes is primarily for low duty cycle sensor and instrument type devices (mostly stationary). STAs whose locations change rapidly should avoid or be more conservative in their use of open-loop link margin indexes. Including the open-loop link margin index in beacon or other management frames may be optional. The new TPC reports need to consider Rx sensitivity for fast-moving STAs.

[0101] As discussed in more detail below, power control methods and procedures for UL random access can be provided. ULMU random access transmissions can be synchronized and scheduled via trigger frames. The TPC procedure for random access, which can be performed using frame exchange between the AP and STA, can be primarily based on an open-loop process. This may be because the AP may not know who can use the ULMU random access time slot for transmission. Where the AP can restrict access to UL MU random access, a certain level of closed-loop TPC procedure can be applied in conjunction with open-loop TPC.

[0102] In one embodiment, a TPC procedure applicable to general UL MU random access can be provided. In another embodiment, procedures and methods are described for situations where the AP can restrict UL MU random access through one or more different criteria, which can mitigate MU TPC. It should be noted that the methods and procedures provided with respect to this embodiment can be applied to any MU power control scheme and should not be limited to UL random access.

[0103] Reference Figure 5 and 6The diagram illustrates the TPC process for random access to a UL MU. In this implementation, the following transmit power control concepts may be included: A baseline transmit (Tx) power can be calculated as a baseline on the non-AP STA side to set the uplink transmit power. The calculation of the baseline Tx power can be based on an open-loop, closed-loop, or combined open-loop / closed-loop power control process. Furthermore, Tx power adjustment values ​​can be used to refine the Tx power adjustment.

[0104] Using UL MU for random access, a STA can access the WLAN system even before the association is triggered by a trigger frame. The STA intending to transmit a UL frame can randomly select one or more OFDMA resource elements according to the instructions of the trigger frame. An OFDMA resource element is a basic resource element that can be assigned to a STA, such as an OFDMARU in an IEEE 802.11ax system. The trigger frame can allow both dedicated and random access transmissions simultaneously. In the embodiment described herein, at least one OFDMA resource element can be assigned for random access.

[0105] STAs transmitted after the trigger frame can utilize the TPC process described here. Figure 5 and 6 An exemplary procedure for random access with power control is illustrated. In this example, AP 602 can acquire a channel with four OFDMA resource elements. In the DL trigger frame 502 sent in step 1, AP 602 can indicate that OFDMA resource elements 1 to 3 can be used for UL MU random access, while the fourth OFDMA resource element can be assigned to STAk 608. In steps 2 and 3, and during the short inter-frame space (SIFS) time following the end of trigger frame 502, the first STA 604 and the second STA 606 can transmit their random access frames on resource elements 504 and 506, respectively. No STA can transmit on resource element 508. In step 4, STAk 608 can transmit on resource element 510. Subsequently, in step 5, AP 602 can send an ACK frame 512 for UL MU transmission.

[0106] The actions performed on the AP side during the TPC process described above can be described herein. AP 602 can acquire the channel medium through contention or scheduling. In step 1, AP 602 can transmit a trigger frame 502 via at least one transmit circuit coupled to at least one antenna. The trigger frame 502 may include the allocation of at least one OFDMA resource element for random access in an upcoming UL OFDMA transmission. The trigger frame 502 can be transmitted using one or more methods described herein.

[0107] like Figure 5As shown, trigger frame 502 can be transmitted as a separate frame. DL transmission of trigger frame 502 can be in OFDM mode. Trigger frame 502 as a MAC frame can be aggregated with other frames, including data frames, control frames, and management frames, using the aggregated MAC Protocol Data Unit (A-MPDU) format. Transmission can be in OFDM mode, OFDMA mode, or another MU mode. AP 602 can transmit trigger frame 502 and other frames, including data frames, control frames, and management frames, in MU mode (e.g., DL OFDMA or another MU mode). If trigger frame 502 is transmitted in DL OFDMA mode, the resource allocation field in the signal field B (SIG-B) of trigger frame 502 can use a reserved broadcast or multicast identifier (ID) to indicate that the corresponding OFDMA resource unit is assigned to trigger frame 502 for transmission. The broadcast or multicast ID used in the SIG-B field can indicate that all STAs 604, 606, and 608 may need to monitor and decode the information carried on the resource unit.

[0108] AP602 can include an open-loop power control index (index 1) in trigger frame 502. In one approach, the open-loop link margin index can be defined in a manner similar to that in IEEE 802.11ah, as follows:

[0109] Δ OPLM =P tx +RX sensitivity Equation (6)

[0110] However, the receiver sensitivity RX sensitivity This can be defined as the minimum required received power for MCS reception with the lowest basic channel bandwidth. For example, for IEEE 802.11ax, it could refer to 20MHz or another bandwidth. This can be standardized, so the definition can be explicitly known for STA 604, 606, and 608. Open-loop link margin Δ OPLM It can be calculated as (-128+D×G)dB, where D can be the open-loop link margin index and G can be the basic granularity. For example, G = 0.25 or 0.5.

[0111] AP 602 may include a power calibration index (index 2) in trigger frame 502. This power calibration index may be a target link margin or the expected received power on the AP side. In the case of UL MU transmission, STA604, 606, and 608 may attempt to reach AP 602 with the target power level.

[0112] AP 602 may include user-specific power adjustment parameters in trigger frame 502. The power adjustment parameters may be the same for all receivers in the random access STA for the resource element assigned to it.

[0113] Following the SIFS time, and as shown in steps 2-4, AP 602 can receive UL transmissions from multiple STAs 604, 606, and 608 via at least one receiving circuit coupled to at least one antenna. STAs 604, 606, and 608 can adjust their transmit power based on the transmit power adjustment value received in the previous trigger frame 502 and the baseline transmit power. On each OFDMA resource element assigned to random access, AP 602 can successfully receive one random access packet from STAs 604, 606, and 608, or receive multiple random access packets from multiple STAs 604, 606, and 608, which may result in a collision on a particular OFDMA resource element, or no packet on that particular OFDMA resource element. On OFDMA resource elements assigned to dedicated STAs 604, 606, and 608, AP 602 can receive data, control, or management frames from the assigned STAs 604, 606, and 608.

[0114] In step 5, and within the SIFS time following the reception of the UL MU transmission, AP 602 may transmit multiple STA acknowledgment frames or block ACK frames to STAs 604, 606, and 608.

[0115] The actions performed on the STA side during the above TPC process can be described here. In step 1, STAs 604, 606, and 608 can detect trigger frame 502 via at least one receiving circuit coupled to at least one antenna. Trigger frame 502 can assign at least one OFDMA resource element for random access to the UL MU in an upcoming UL OFDMA transmission. If the DL transmission from AP 602 is in OFDMA mode, STAs 604, 606, and 608 can verify the SIG-B field of the resource allocation in trigger frame 502. If the first STA 604 and the second STA 606 have uplink control, management, or data frames to transmit, STAs 604 and 606 can prepare for the transmission in the assigned UL MU random access resource using at least one transmitting circuit coupled to at least one antenna. Furthermore, if the first STA 604 and the second STA 606 meet the random access requirements in trigger frame 502 (if any), the first STA 604 and the second STA 606 can prepare for the transmission. In steps 2 and 3, the first STA 604 and the second STA 606 can transmit in the assigned UL MU random access resource using at least one transmitting circuit coupled to at least one antenna. If STAk 608 is not assigned a transmission opportunity or dedicated OFDMA resource unit by AP 602 for an upcoming UL transmission, STAk 608 can prepare for the transmission. In step 4, STAk 608 can transmit.

[0116] When transmissions occur in one or more of the assigned random access resource units in accordance with the UL MU random access protocol in the first STA 604 and the second STA 606, a padding scheme can be applied to the uplink transmission, thereby enabling transmissions from multiple users to be completed at the same time or substantially at the same time.

[0117] STAs 604, 606, and 608 can set the transmit power according to the methods disclosed herein. STAs 604, 606, and 608 can verify the value of index 1 carried in trigger frame 502. STAs 604, 606, and 608 can verify the value of index 2 carried in trigger frame 502. STAs 604, 606, and 608 can calculate the baseline transmit power based on index 1 and index 2. STAs 604, 606, and 608 verify the power adjustment parameters carried in trigger frame 502 and increase or decrease the baseline transmit power accordingly.

[0118] If STAs 604, 606, and 608 have previously communicated with AP 602 (e.g., within a certain time period), STAs 604, 606, and 608 may have a record of parameters related to historical transmit power control. STAs 604, 606, and 608 may weight one or more of the historical transmit power control-related parameters and combine them with the instantaneous transmit power obtained from any one or more of the parameters or values ​​received from trigger frame 502.

[0119] STAs 604, 606, and 608 can adjust the calculated transmit power based on the transmission bandwidth and antenna settings. STAs 604, 606, and 608 can verify that the calculated transmit power does not violate the maximum permissible transmit power and transmit power density. Otherwise, STAs 604, 606, and 608 can use the maximum permissible transmit power.

[0120] After the SIFS time following the transmission, STAs 604, 606, and 608 can receive an acknowledgment frame from AP 602.

[0121] In one embodiment, trigger frame 502 may include index 1 and index 2. In another embodiment, trigger frame 502 may include index 2 but not index 1. Instead, AP 602 may broadcast index 1 in a beacon frame. STAs 604, 606, and 608 may need to detect at least one beacon frame before trigger frame 502, which may initiate uplink random access from STAs 604, 606, and 608. In this scenario, trigger frame 502 may be transmitted for calculating the transmit power of index 1. Therefore, STAs 604, 606, and 608 can measure the received power of trigger frame 502 and calculate the baseline transmit power accordingly. In another embodiment, trigger frame 502 may include neither index 1 nor index 2. Instead, AP 602 may broadcast index 1 in a beacon frame.

[0122] The TPC process described above can be applied to the UL data section. However, it should be noted that these processes can also be applied to the UL preamble section using a scaler. Legacy preambles and high-efficiency (HE) preambles can use different scalers.

[0123] This document discloses a method and procedure for setting the baseline transmit power. For UL random access, AP 602 may not know which STAs 604, 606, and 608 can transmit at which time. Therefore, it is difficult for AP 602 to adjust the transmit power of STAs 604, 606, and 608. Instead, AP 602 can broadcast the necessary information from STAs 604, 606, and 608 to set the baseline transmit power. This allows the receive power on the AP 602 side to be calibrated in the upcoming UL MU transmission time slot. The baseline power setting can be an open-loop process involving DL transmissions from non-AP STAs 604, 606, and 608 for measuring receive power and setting transmit power.

[0124] In DL transmission, two power control-related parameters can be included and broadcast to STA604, 606, and 608. The open-loop power control index (index 1) can be calculated based on, for example, the transmit power on the AP 602 side, the transmit / receive antenna gain on the AP 602 side, the bandwidth information required for DL ​​transmission, and / or cable and connector losses. Based on this index, given the transmit power of STA604, 606, and 608, the receiver can estimate the path loss between STA 604, 606, 608 and AP 602, as well as the desired receive power level on the AP 602 side.

[0125] AP 602 can be configured with a power calibration index (index 2), which can be used by multiple STAs 604, 606, and 608 to calibrate the received power on the AP 602 side. This index can be the link margin or desired received power on the AP 602 side for UL MU transmission. For example, if the first STA 604 uses power P... _tx_1 According to index 1, the first STA 604 can expect the received power on the AP 602 side to be P. _rx_1 And if the second STA 606 uses power P _tx_2 Transmitting, the second STA 606 can expect the received power on the AP 602 side to be P. _rx_2 According to index 2, the first STA 604 and the second STA 606 can observe that AP 602 can expect a received power of C. The first STA 604 can adjust its transmit power to P. _tx_1 -(P _rx_1 -C), and similarly, the second STA 606 can adjust its transmit power to P. _tx_2 -(P _rx_2 -C).

[0126] Several examples of setting open-loop power control indices (index 1) and power calibration indices (index 2) are disclosed. Furthermore, detailed link budget calculations for multi-user transmission can be expressed by the following formula.

[0127] Reference Figure 7 The illustration shows the transmission of TPC information, index 1, and index 2, as well as the transmission power settings of one or more STAs. In one embodiment, AP 602 may transmit TPC information, index 1, and index 2 to at least STAs 604, 606, and 608 in a DL trigger frame. STAs 604, 606, and 608 may accordingly set their transmission power in the subsequent UL random access transmission.

[0128] like Figure 7 As shown, AP 602 can broadcast a trigger frame allocating at least one OFDMA resource element for UL random access. Index 1 and Index 2 can be indicated in the trigger frame. In an alternative approach, Index 2 may not be included, and a default Index 2 may be specified or negotiated individually between AP 602 and one or more of STAs 604, 606, and 608. When measuring the received power of the DL trigger frame, the k-th STA 702 can estimate the path loss (PL) between AP 602 and the k-th STA 702 as follows:

[0129] PL k =P tx_ap +AP tx_antenna_gain +STA rx_antenna_gain_k -P rx_sta_k Equation (7)

[0130] Where P tx_ap This is the transmit power on the AP 602 side. tx_antenna_gain This refers to the antenna gain on the AP 602 side, STA rx_antenna_gain_k It is the antenna gain on the k-th STA 702 side, and P rx_sta_k It is the received power on the k-th STA 702 side.

[0131] It should be noted that losses such as cable loss and connector loss are not considered in equation (7). However, where they may need to be considered, they can be assumed to be included in the antenna gain parameter. For example, AP tx_antenna_gain It can be interpreted as AP tx_antenna_gain –AP tx_cable_loss Similarly, STA rx_antenna_gain_k It can be interpreted as STA rx_antenna_gain_k –STA rx_cable_loss_k .

[0132] It can be assumed that AP 602 is transmitting on a channel with a bandwidth M_DL corresponding to N_DL subcarriers, while the k-th STA 702 can perform a received power measurement on the same channel bandwidth.

[0133] In the next time slot, if the k-th STA 702 transmits on one or more OFDMA resource elements with a bandwidth M_UL corresponding to N_UL subcarriers, the expected received power on the AP 602 side can be expressed as follows:

[0134] P rx_ap_k =P tx_sta_k +STA tx_antennA_gAin_k +AP rx_antenna_gain -PL k

[0135] =P tx_sta_k +STA tx_antenna_gain_k +AP rx_antenna_gain -(P tx _ ap +AP tx_antenna_gain

[0136] +STA rx_antenna_gain_k -P rx_sta_k )

[0137] =(P tx_sta_k +P rx_sta_k +STA tx_an t enna_gain_k -STA rx_antenna_k )+(AP rx_antenna_gain

[0138] -AP tx_antenna_gain -P tx_ap )

[0139] =A+B,

[0140] Equation (8)

[0141] Where A = P tx_sta_k +P rx_sta_k +STA tx_antenna_gain_k -STA rx_antenna_k Equation (9)

[0142] And B = -P tx_ap +AP rx_antenna_gain -AP tx_antenna_gain Equation (10)

[0143] As listed, P tx_sta_k It could be the transmit power at the k-th STA 702. This could be the received power at the k-th STA702. tx_antenna_gain_k This could be the transmit antenna gain on the k-th STA 702 side, and the STA rx_antenna_k This could be the receive antenna gain on the k-th STA 702 side. P tx_ap It could be the transmit power on the AP 602 side, APrx_antenna_gain This could be the receive antenna gain on the AP 602 side, and the AP... tx_antenna_gain It could be the transmit antenna gain on the AP 602 side.

[0144] The expected link margin on the STA side can be:

[0145] LM ap_k =P rx_ap_k -sensitivity ap =A+(B-sensitivity) ap Equation (11)

[0146] Among them, sensitivity ap This could be the sensitivity on the AP 602 side. The value of A can be known on the k-th STA 702 side, while the value of B can be known on the AP 602 side. If the AP 602 can broadcast the desired received power, index 2 for arrivals of STAs 604, 606, 608, and 702, the k-th STA 702 side might need to know the values ​​of A and B. In other words, the AP 602 can include B or related information as index 1 in the DL transmission. Alternatively, if the AP 602 can broadcast the desired link margin (index 2) for arrivals of STAs 604, 606, 608, and 702, the AP 602 can include B – sensitivity – in the DL transmission. ap Or related information as index 1.

[0147] Value P tx_ap and P rx_sta_k It can be the power transmitted or measured through the same bandwidth, which can be the DL transmission bandwidth.

[0148] If the transmit antenna gain and receive antenna gain are the same on the AP 602 side, or if the system can be considered to have them as the same, then B can be simplified to:

[0149] B = -P tx_ap Equation (12)

[0150] If the transmit antenna gain and receive antenna gain are the same on the k-th STA 702 side, or if the system can be considered to have them as the same, then A can be simplified to:

[0151] A = P tx_sta_k +P rx_sta_k Equation (13)

[0152] There are two ways to set index 1 and index 2. In one implementation, index 1 and index 2 can be set based on power. For example, index 1 can be set based on the value B defined in equation (10) or equation (12). Index 2 can be the desired received power or link margin. For OFDMA transmission, the DL and UL transmission bandwidths can be different, so BW adjustment can be applied.

[0153] In one embodiment, AP602 may have an asymmetric transmit and receive antenna configuration. Index 1 can be B = -P in decibels relative to 1 mW. tx_ap +AP rx_antenna_gain -AP tx_antenna_gain (B = -P) tx_ap +AP rx_天线_增益 -AP tx_天线_增益 A quantized version of P. tx_ap A detailed definition could be the transmit power used to transmit frames containing index 1. The AP602 can include the transmit bandwidth in the PLCP header, while P... tx_ap This could be the transmission power across the entire band. P tx_ap This could be the transmit power of each subcarrier used to transmit frames containing index 1. P tx_ap This can be the equivalent transmit power for transmitting frames containing index 1, relative to the basic bandwidth. The basic bandwidth can be defined as a mandatory supported bandwidth. For example, the basic bandwidth could be 20MHz, while the AP 602 could transmit on a 40MHz channel. Then P... tx_ap It can be the transmit power on a 20MHz basic channel, which can be 3dB less than the total transmit power on a 40MHz channel.

[0154] Index 2 can be a function or quantized version of the expected received power C, measured in decibels relative to 1 mW. The variable C can be the expected segment received power over the expected total bandwidth with N total subcarriers for an upcoming ULMU transmission, regardless of whether the UL transmission bandwidth is narrower than or the same as the expected bandwidth from AP 602. For example, AP 602 can reserve an 80 MHz channel for an upcoming UL MU transmission. AP 602 can allocate some OFDMA resource units for the ULMU random access transmission. Therefore, some of the OFDMA resource units may not be selected by any STA 604, 606, 608, or 702, and this can result in a real UL transmission bandwidth less than 80 MHz. However, C in this example can be the expected received power over an 80 MHz channel (but not the bandwidth utilized in the UL MU transmission).

[0155] Variable C can be the expected received power on a basic bandwidth (with N basic subcarriers) that is independent of the upcoming UL MU transmission bandwidth. This basic bandwidth can be defined as a mandatory supported bandwidth. For example, the basic bandwidth could be 20 MHz. This basic bandwidth can be specified in the standard or negotiated between AP 602 and all STA604, 606, 608, and 702 prior to the transmission. In one approach, AP 602 can broadcast it in a beacon frame.

[0156] Variable C can be the expected received power on the smallest OFDMA resource unit with N_ unit subcarriers, which is independent of the upcoming UL MU transmission bandwidth.

[0157] Variable C can be the expected received power on a subcarrier that is independent of the upcoming UL MU transmission bandwidth.

[0158] The k-th STA702, acting as the receivers at indices 1 and 2, can set its baseline transmit power on one or more OFDMA resource units using the procedures disclosed herein. The k-th STA702 can obtain the value B from index 1. The k-th STA702 can obtain the value C from index 2. The baseline transmit power of this STA, measured in decibels relative to 1 mW, can be:

[0159] P baseline_k =CBP rx _ sta_k -(STA tx_antenna_gain_k -STA rx_antenna_gain_k )-

[0160] 10log 10 M+10log 10 N

[0161] Equation (14)

[0162] In equation (14), N can be the number or bandwidth of the k-th STA 702 used for UL transmission. M can be the number or bandwidth of the subcarriers at index 2. When C can be the expected received power over the expected total bandwidth, M = N - total. When C can be the expected received power over the basic bandwidth, M = N - basic. When C can be the expected received power over the minimum OFDMA resource unit, M = N - unit. When C can be the expected received power over the subcarriers that are not related to the upcoming ULMU transmission bandwidth, M = 1. When the transmit antenna gain and receive antenna gain on the STA side can be the same or can be considered to be the same, equation (14) can be simplified to the form shown in equation (15).

[0163] Pbaseline_k =CBP rx_sta_k -10log 10 M+10log 10 Equation (15)

[0164] In one embodiment, AP 602 may have a symmetrical transmit and receive antenna configuration. This embodiment can be similar to the methods disclosed for asymmetrical transmit and receive antenna configurations, except that it can be assumed that the transmit antenna gain and receive antenna gain on the AP 602 side can be the same or considered to be the same. In this case, index 1 can be the following quantized version:

[0165] B = -P tx_ap Equation (16)

[0166] The variable B can be expressed in decibels relative to 1 mW. The baseline power calculation can follow equation (14) or equation (15), where the value B can be replaced by equation (16).

[0167] In another embodiment, index 1 and index 2 can be set based on the link margin (LM) of the difference between the received power and the receiver sensitivity, and can be defined as follows:

[0168] LM ap =P rx_ap_k -sensitivity ap Equation (17)

[0169] Sensitivity ap (sensitivity) ap Index 1 can be the receiver sensitivity on the AP 602 side. Index 1 can be set to the value B minus a certain level of receiver sensitivity, while index 2 can be the expected link margin on the AP 602 side. Receiver sensitivity can be a function of MCS level and channel bandwidth. In OFDMA systems, different OFDMA resource unit sizes can also affect the sensitivity value. Detailed methods and procedures are disclosed here.

[0170] In one embodiment, the AP may have an asymmetric transmit and receive antenna configuration, and index 1 may be the following quantization version in decibels:

[0171] B1 = B-sensitivity ap

[0172] =-P tx_ap -sensitivity ap +AP rx_antenna_gain -AP tx_antenna_gain Equation (18)

[0173] Alternatively, index 1 can be a function of B1. P tx_ap and sensitivity ap A detailed definition of P may be one or more of the definitions published here. tx_ap This could be the transmit power used to transmit frames containing index 1. The AP602 can include the transmit bandwidth in the PLCP header, while P... tx_ap This could be the transmission power across the entire band. P tx_ap This could be the transmit power of each subcarrier used to transmit frames containing index 1. P tx_ap This can be the equivalent transmit power for transmitting frames containing index 1, relative to the basic bandwidth. The basic bandwidth can be defined as a mandatory supported bandwidth. For example, the basic bandwidth could be 20MHz. (sensitivity) ap This can be the minimum required receive power for the minimum MCS bandwidth used to transmit frames containing index 1. ap This can be the minimum required receive power for the minimum MCS used to receive a subcarrier. (sensitivity) ap This can be the minimum required received power for the minimum MCS (Medium-Size) of the basic bandwidth. The basic bandwidth can be defined as the bandwidth that is mandatory. For example, the basic bandwidth could be 20MHz.

[0174] Index 2 can be a quantized version of the expected receiver link margin with a value C1, expressed in decibels relative to 1 mW. Alternatively, Index 2 can be a function of C1. The detailed definition of C1 can be any of the definitions disclosed herein. C1 can be the expected link margin for an upcoming UL MU transmission with an expected total bandwidth of N_ total number of subcarriers, even if the bandwidth of the UL transmission is narrower than or equal to the expected bandwidth from AP 602.

[0175] For example, AP 602 can reserve an 80MHz channel for an upcoming UL MU transmission. AP 602 can allocate some OFDMA resource cells for the UL MU random access transmission. Therefore, some of the OFDMA resource cells may not be selected by any STA604, 606, 608, or 702, and this can result in the actual UL transmission bandwidth being less than 80MHz. However, C1 in this example could be the desired received power on the 80MHz channel (but not the bandwidth utilized in the ULMU transmission).

[0176] C1 can be the expected link margin on a basic bandwidth with N basic subcarriers that is independent of the upcoming UL MU transmission bandwidth. The basic bandwidth can be defined as a mandatory supported bandwidth. For example, the basic bandwidth can be 20 MHz. This basic bandwidth can be normalized, either by AP 602 in a beacon frame prior to the transmission, or negotiated between AP 602 and all STAs 604, 606, 608, and 702 prior to the transmission. C1 can be the expected link margin on the smallest OFDMA resource unit with N unit subcarriers that is independent of the upcoming UL MU transmission bandwidth. Alternatively, C1 can be the expected link margin on subcarriers that is independent of the upcoming UL MU transmission bandwidth.

[0177] When receiving indices 1 and 2, the k-th STA 702 can set its baseline transmit power on one or more OFDMA resource elements having N subcarriers using the procedures disclosed herein. The k-th STA 702 can obtain B1 from index 1. The k-th STA 702 can obtain C1 from index 2. The transmit power of the k-th STA 702, in decibels relative to 1 mW, can be calculated as follows:

[0178] P baseline_k =C1-B1-P rx_sta_k -(STA tx_antenna_gain_k -STA rx_antenna_gain_k )-

[0179] 10log 10 M+10log 10 Equation (19)

[0180] In equation (19), N can be the number or bandwidth of subcarriers used by the k-th STA 702 for UL transmission. M can be the number or bandwidth of subcarriers at index 2. M = N_total when C1 is the expected link margin on the anticipated total bandwidth (with N_total subcarriers) for the upcoming UL MU transmission, even if the UL transmission bandwidth is narrower than or equal to the expected bandwidth from AP602. M = N_basic when C1 is the expected link margin on the basic bandwidth (with N_basic subcarriers) that is independent of the upcoming UL MU transmission bandwidth. M = N_unit when C1 is the expected link margin on the smallest OFDMA resource unit (with N_unit subcarriers) that is independent of the upcoming UL MU transmission bandwidth. M = 1 when C1 is the expected link margin on subcarriers that are independent of the upcoming UL MU transmission bandwidth.

[0181] If the transmit antenna gain and receive antenna gain on the k-th STA702 side can be the same or can be considered the same, equation (19) can be simplified to:

[0182] P baseline_k =C1-B1-P rx_sta_k -10log 10 M+10log 10 N. Equation (20)

[0183] In one embodiment, AP602 may have a symmetrical transmit and receive antenna configuration. This embodiment can be similar to embodiments involving asymmetrical transmit and receive antenna configurations, except that it can be assumed that the transmit antenna gain and receive antenna gain on the AP602 side can be the same or considered to be the same. In this case, index 1 can be the following quantized version in decibels:

[0184] B1 = -P tx_ap -sensitivity ap Equation (21)

[0185] The baseline transmit power calculation can follow equation (19) or equation (20), where the value B can be replaced by equation (21). It should be understood that equation (21) is negative for the open-loop link margin. Therefore, for this method, the open-loop link margin can also be used as index 1, and equations (19) and (20) can be slightly modified to take into account the negative sign.

[0186] The method and procedure for setting power adjustment are disclosed here. The power adjustment parameter can be set to an integer or fraction in decibels, denoted as D. Alternatively, the power adjustment parameter can be a function of D. If AP 602 does not have any power control-related records for STAs or if AP 602 does not know which STAs can transmit, for example, via UL MU random access, the value D can be set using a default value. The value D can be increased as the number of retries increases. For example, AP 602 can use random access to trigger retransmissions from STAs 604, 606, 608, and 702.

[0187] The TPC procedure with restricted UL MU random access is disclosed herein. Consideration Figure 5-7The UL MU random access procedure is initiated by a trigger frame, which discloses the process by which a STA, such as the first STA 604, determines whether it is a candidate for a UL MU random access opportunity. One aspect of this process may include power control information in the trigger frame that the first STA 604 can use to determine its UL MU random access opportunity status. The power control information may indicate the range of permissible received power at the first STA 604 and / or the link margin that the first STA 604 can incorporate. This is in... Figure 8 It is shown in the middle.

[0188] Figure 8 An APTx power range 802 is shown, wherein STA604, 606, 608, and 702, having an Rx power range 804 corresponding to the Tx power range 802, may be permitted to transmit for ULMU random access. The Tx power range 802 may be part of the total APTx power range 806, wherein AP 602 may transmit. The Rx power range 804 may be part of the total STARx power range 808.

[0189] Information used to determine the Rx power range 804 and / or link margin may include maximum path loss, ΔPLM, link margin in dB, link margin index with positive integer values ​​(e.g., 0-128), and SNR margin that may include the received SNR relative to receiver sensitivity.

[0190] The range can be specified using any combination or all of the information disclosed here. For example, the range of the link margin index can be defined as follows:

[0191] Link Margin Range(0-256)=Link Margin max -Link Margin min Equation (22)

[0192] For this definition, STA 604, 606, 608, and 702 may have to anticipate exceeding the link margin. min (Margin 最小值 And it is within the link margin range for its inclusion in the UL MU random access pool.

[0193] AP 602 can also indicate transmit power, denoted as P. tx_ap This is used to transmit trigger frames. STAs 604, 606, 608, and 702 with receive power within this range can set their transmit power to P in the upcoming random access frame. tx_sta =P tx_apAlternatively, in the trigger frame, AP 602 can indicate the transmit power (P) used to transmit the trigger frame. tx_ap ) and power bias (P delta STAs 604, 606, 608, and 702, which have receive power within this range, can set their transmit power to P in the upcoming random access frame. tx_sta =P tx_ap –PΔ. It should be noted that the additional bandwidth and antenna gain can be counted.

[0194] In one implementation, a TPC for UL MU random access is disclosed. For example, the STA 602 and AP 602 of the k-th STA 702 may indicate their power control capabilities for UL MU random access. AP 602 may include an indicator in its beacon, probe response, association response, or any other type of frame indicating that AP 602 is capable of power control (more specifically, power control for UL MU random access). The UL MU random access TPC capability indicator may be included in any existing or new field, such as an information element (IE) in management, control, or other frame types. The UL MU random access TPC capability indicator may be included in a MAC or PLCP header. Similarly, the k-th STA 702 may also indicate TPC capability for UL MU random access using one or more indicators in probe requests, association requests, or other management, control, or other frame types. The k-th STA 702 may indicate TPC capability for UL MU random access in a MAC or PLCP header.

[0195] The following description may include updated TPC reports for IEEE 802.11ax and open-loop TPC corrections. The implementation described herein addresses transmit power control for fast-moving STAs.

[0196] In the IEEE 802.11 specification, a STA wishing to transmit can send a TPC request to a receiving STA. The receiving STA can then reply with information in a TPC report frame to ensure the transmitting STA transmits at the correct transmit power. The use of TPC report frames in IEEE 802.11h can produce information that does not include receiver sensitivity. The open-loop link margin index in IEEE 802.11ah can address this issue but may not be suitable for fast-moving STAs. In IEEE 802.11ax, where the receiver sensitivity can be what fast-moving STAs with different MCS require, there may be a need to modify the TPC report to achieve complete information transmission. Without loss of generality, it should be assumed that the STA will be willing to transmit to the AP acting as the receiver.

[0197] For downlink transmission, the received signal strength RSSI at the STA STA It can be defined as:

[0198] RSSI STA =P tx-AP -Ploss→RSSI STA =Ploss=P tx-AP -RSSI STA Equation (23)

[0199] Where P tx-AP It can be the transmit power at the AP, while Ploss can be the path loss, which can include shadowing and fast fading between the STA and the AP.

[0200] For uplink transmission, the received signal strength (RSSI) at the AP is... AP It can be defined as:

[0201] RSSI AP =P tx-STA -Ploss, Equation (24)

[0202] Where P tx-STA This can be the transmit power at the STA. The link margin (ΔMCS) can be defined as the receive power at the AP and the decoding expectation MCS (R). req The difference between the required power and the actual power:

[0203] RSSI AP -R req =ΔMCS→RSSI AP =ΔMCS+R req Equation (25)

[0204] Combining these equations, we get:

[0205] P tx-STA -P tx-AP +RSSI STA =ΔMCS+R req Equation (26)

[0206] and

[0207] P tx-STA =ΔMCS+P tx-AP +R req -RSSI STA Equation (27)

[0208] Send ΔMCS, P tx-AP and R reqThis allows the STA to estimate the correct transmit power. This can be sent separately to the STA in the frame of the new TPC report. Alternatively, the existing TPC report sends the transmit power (P) to the AP or receiver. tx-AP ) and MCS link margin (ΔMCS). The existing open-loop link margin index sends the sum of transmit power and receiver requirements to the AP or receiver (P). tx-AP +R req Therefore, even for fast-moving STAs, sending the MCS link margin and open-loop link margin index can give the STA or transmitter enough information to correctly estimate its transmit power.

[0209] In one implementation, a new TPC report, such as that used in IEEE 802.11ax, can be employed. The TPC report frame format may include an element ID, length, and an Open-Loop Link Margin Index (OLLMI), which is equal to:

[0210] OLLMI=P tx_ap +Rx sensitivity_mcs =P tx_ap +ΔMCS, Equation (28)

[0211] And the link margin is equal to:

[0212] Link Margin = RSSI AP -Rx sensitivity_mcs =RSSI AP -ΔMCS. Equation (29)

[0213] Rx related to MCS sensitivity (Rx 灵敏度 Additional information, including available transmit power headroom, can be transmitted. For Rx related to MCS... sensitivity The TPC request can be updated to include the Rx sensitivity that should be sent to the MCS targeted in the TPC report.

[0214] In another exemplary frame format, a frame may include an element ID, length, and transmit power = P. tx-AP Link margin, which in equation (30) is equal to the above-defined value, and Rx sensitivity =R req For example, in the first format, it is used for MCS. used_for_Rx_sensitivity (MCS 用于_Rx_灵敏度 Fields for available transmit power margin can also be added.

[0215] The AP or STA decides which of the specific parameters to send back (e.g., ΔMCS, P) tx-AP Or R reqIn this case, the frame format can be constructed to send back any combination of three parameters and a bitmap, which indicates which of the three parameters are sent to limit the number of fields fed back. In one implementation, the 3-bit bitmap can be used to specify whether transmit power, link margin, and / or link margin index are sent, as shown in Table 1.

[0216] Table 1: Bitmap of information reported in the TPC report

[0217] Tx power Link margin Link margin index 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1

[0218] This bit format can be included as part of the element ID or as part of the frame itself. This bitmap can determine the size of the feedback frame. As an example, if the AP transmit power remains constant, there may be no need for feedback AP transmit power, and the first bit is typically set to 0.

[0219] Different STAs can be implemented using different TPCs, and the transmit power estimated based on the TPC report can produce RSSIs that differ from the expectations. AP Additional methods may be needed to verify that the correct power level is being set by a single STA.

[0220] In one implementation, the receiver can determine the desired received power and send an instruction to the transmitter to adjust its power by the desired amount. This can be a closed-loop method.

[0221] In one implementation, the transmitter may wish to ascertain whether its RSSI estimate at the transmitter is correct. This can be an open-loop method. The following description may include an open-loop correction process to achieve this open-loop verification of the signal level received by the receiver. An open-loop correction frame may be sent to the receiver to ensure that the received power is equal to what the receiver expects. In this case, the transmitting STA may issue a correction request to the receiver, and the receiver may respond with a metric indicating the received power to the transmitting STA. The metric may be based on power received from the STA and as simply as the RSSI of the AP. Alternatively, the transmitter may send information at the receiver's expected level, and the receiver may subsequently respond with information about the difference, or whether the visible value is greater than or less than the requested value. The transmitting STA may then use this information to correct its transmit power.

[0222] The following description may include procedures that can be used between a transmit-receive pair. The transmitter may send a TPC request to the receiver. In one embodiment, the TPC request may be a simple frame with a specific element ID and no additional information. Alternatively, the TPC request may explicitly request specific information, such as transmit power, link margin for a specific MSC, and / or link index. The receiver may send an updated TPC report from the transmitter. Immediately or after a delay, the transmitter may send a TPC correction request to the receiver. This may be a simple request frame, or it may include information about the expected RSSI at the receiver based on information received in the TPC report.

[0223] The receiver can send an acknowledgment that includes information to help correct the STA's open-loop power control. This information can be a simple bit indicating whether the received signal level is greater than, less than, or equal to the desired received power. Alternatively, this information can be the power difference between the desired and actual received power. In one embodiment, feedback can continue until the desired power is reached. In one embodiment, the correction frame can be a simple request to increase or decrease the STA's transmit power by a desired amount.

[0224] The following description may include power control methods and procedures for UL MU OFDMA transmissions. Implementations can address problems arising from power control in UL MU transmissions. In one implementation, a TPC procedure is proposed for UL MU OFDMA transmissions, which may include data frames or control frames. The method and procedure can be implemented when all OFDMA transmissions are assigned by the AP.

[0225] TPC information can be included in UL data frames, such as... Figure 9 The trigger frame shown, or the control frame included Figure 10 and Figure 11 The preamble or DL ​​DATA / DL MU RTS shown. For Figure 11 The cascaded transmissions shown can have their transmit power control information for each UL transmission within the cascade trigger. In the case of cascaded transmissions, if the STA is repeated, the TPC adjustment value can be used in the published correction frame to correct for any errors in the original transmission. The transmit power control information may include any information disclosed herein.

[0226] Now refer to Figure 9 The diagram illustrates the TPC process for a UL data frame. Figure 9An exemplary procedure for UL MU-OFDMA data transmission with power control is illustrated. In this example, the AP can acquire a channel with four OFDMA resource units. In DL trigger frame 902, the AP can assign OFDMA resource units 1-4 to a specific user. During the SIFS duration following the reception of trigger frame 902, the STA can send information to the AP in UL data frames 904-910 using the TPC and assignment information provided in trigger frame 902. Subsequently, the AP can send a UL MU transmission acknowledgment frame 912.

[0227] The AP-side procedures for the TPC process of the UL data frame described above are disclosed herein. The AP can acquire the channel medium through contention or scheduling. The AP can transmit a trigger frame. The trigger frame can be transmitted using one or more methods disclosed herein. The trigger frame can serve as... Figure 9 The individual frames shown are transmitted. DL transmission can be in OFDM mode. In one embodiment, the trigger frame, as a MAC frame, can be aggregated with other frames, including one or more data frames, control frames, and / or management frames, using the A-MPDU format. This transmission can be in OFDM mode, OFDMA mode, or another MU mode. The AP can transmit the trigger frame and other frames, including data frames, control frames, and management frames, in MU mode (e.g., DL OFDMA or another MU mode). If the trigger frame is transmitted in DL OFDMA mode, the resource allocation field in the SIG-B field of the trigger frame can use a reserved broadcast or multicast ID to indicate that the corresponding OFDMA resource unit is assigned for the trigger frame transmission. The broadcast or multicast ID used in the SIG-B field can indicate that all STAs may need to monitor and decode the information carried on the resource unit.

[0228] The AP can include an open-loop power control index (index 1) in the trigger frame. In one approach, the open-loop link margin index can be defined in a manner similar to IEEE 802.11ah:

[0229] Δ OPLM =P tx +RX sensitivity Equation (30)

[0230] However, the receiver sensitivity RX sensitivity This can be redefined as the minimum required received power for the minimum MCS (Mean Switching Size) relative to the basic channel bandwidth. For example, for IEEE 802.11ax, it could refer to 20MHz or some other bandwidth. This can be standardized so that the STA (Standard Operating System) clearly understands the definition. Open-loop link margin Δ OPLMIt can be calculated as (-128+D×G)dB, where D can be the open-loop link margin index, and G can be the basic granularity. For example, G = 0.25 or 0.5.

[0231] The AP can include a power calibration index (index 2) in the trigger frame. This power calibration index can be the target link margin or the expected received power on the AP side. In the case of UL MU transmission, all STAs can attempt to reach the AP using the target power level.

[0232] The AP can include user-specific power adjustment parameters in the trigger frame. For resource elements assigned to random access STAs, the power adjustment parameters can be the same across random access STAs. The power adjustment parameters can be the same or different for all receivers in the trigger frame.

[0233] The AP can include any of the aforementioned updated TPC report frames. After the SIFS time, the AP can receive UL transmissions from multiple STAs, and the STAs can adjust their transmit power based on the baseline transmit power and the transmit power adjustment value received in the previous trigger frame. On the OFDMA resource unit assigned to a dedicated STA, the AP can receive data, control, or management frames from the assigned STA.

[0234] During the SIFS time following the reception of the UL MU transmission, the AP can transmit multiple STA acknowledgment frames or block ACK frames to the STA.

[0235] The STA-side procedure for the aforementioned TPC process for UL data frames is disclosed herein. The STA can detect a trigger frame and assign it at least one OFDMA resource unit for random access to the UL MU in an upcoming UL OFDMA transmission. In the case of a DL transmission from the AP in OFDMA mode, the STA can check the SIG-B field for resource allocation of the trigger frame.

[0236] If a STA has one or more uplink control, management, or data frames to transmit, the STA may prepare to transmit them in the assigned UL MU random access resource.

[0237] The STA can set the transmit power according to any method disclosed herein. The STA can verify the value of index 1 carried in the trigger frame. The STA can verify the value of index 2 carried in the trigger frame. The STA can calculate the baseline transmit power based on index 1 and index 2. The STA can verify the power adjustment parameters carried in the trigger frame and increase or decrease the baseline transmit power accordingly. If the STA communicates with the AP during a certain time period, the STA can have recorded transmit power-related parameters. The STA can weight historical transmit power control-related parameters and combine them with the instantaneous transmit power obtained from any one or more parameters or values ​​received from the trigger frame. The STA can adjust the calculated transmit power according to the transmit bandwidth and antenna settings. The STA can verify that the transmit power calculated by any disclosed method does not violate the maximum permissible transmit power and transmit power density. Otherwise, the STA can use the maximum permissible transmit power instead.

[0238] After the SIFS time following this transmission, the AP can receive an acknowledgment frame from the STA.

[0239] Now refer to Figure 10 The diagram illustrates the TPC process for a UL control frame (e.g., an ACK frame). Figure 10 An exemplary procedure for a UL MU-OFDMA control transmission with power control is further illustrated. In this example, the AP can acquire a channel with four OFDMA resource elements and can transmit DL data 1004-1010 to four different STAs. During the SIFS duration following the arrival of DL data 1004-1010 at the STAs, the STAs can send acknowledgment frames 1012-1018 for the DL MU transmission to the AP. The STAs can use TPC information placed in the preamble 1002 sent to all STAs or in the user-specific PHY header sent in each of the DL data frames 1004-1010 to estimate the correct transmit power to use.

[0240] The AP-side procedure for the aforementioned TPC process for the UL control frame is disclosed herein. The AP can acquire the channel medium through contention or scheduling. The AP can transmit preamble 1002 and / or one or more DL data frames 1004-1010 to the user. The AP can include an open-loop power control index (index 1) in one or more of the preamble 1002 and / or DL ​​data frames 1004-1010. In one method, the open-loop link margin index can be defined in a manner similar to IEEE 802.11ah:

[0241] Δ OPLM =P tx +RX sensitivity Equation (31)

[0242] However, the receiver sensitivity RX sensitivity This can be redefined as the minimum required received power for MCS reception with the lowest basic channel bandwidth. For example, for IEEE 802.11ax, it could refer to 20MHz or another bandwidth. This can be standardized so that the STA can explicitly know the definition. Open-loop link margin Δ OPLM It can be calculated as (-128+D×G)dB, where D can be the open-loop link margin index and G can be the basic granularity. For example, G = 0.25 or 0.5.

[0243] The AP may include a power calibration index (index 2) in one or more of the preamble 1002 and / or DL ​​data frames 1004-1010. This power calibration index may be the target link margin or the expected received power on the AP side. In the case of UL MU transmission, all STAs may attempt to reach the AP using the target power level.

[0244] The AP may include user-specific power adjustment parameters in one or more of the preamble 1002 and / or DL ​​data frames 1004-1010. The power adjustment parameters may be the same among random access STAs for resource elements assigned to them. The power adjustment parameters may be the same or different for all receivers of one or more DLs of the preamble 1002 and / or data frames 1004-1010. The AP may include any of the updated TPC report frames disclosed above.

[0245] After SIFS time, the AP can receive ULACK 1012-1018 from multiple STAs, and the STAs can adjust their transmit power based on the baseline transmit power and the transmit power adjustment value received in one or more of the previous preamble 1002 and / or DL ​​data frames 1004-1010.

[0246] The STA-side procedure for the aforementioned TPC procedure for UL control frames is disclosed herein. The STA can detect one or more of the trigger frame, preamble 1002, or DL ​​data frames 1004-1010. The trigger frame can assign at least one OFDMA resource unit for random access of the UL MU in an upcoming UL OFDMA transmission. When the UL transmission from the AP is in OFDMA mode, the STA can verify the SIG-B field for resource allocation in the trigger frame.

[0247] If a STA has one or more uplink control, association, or data frames to transmit, the STA can prepare for transmission in the assigned UL MU random access resource.

[0248] The STA can set the transmit power according to the publicly available method. The STA can verify the value of index 1 carried in one or more of the preamble 1002 or DL ​​data frames 1004-1010. The STA can verify the value of index 2 carried in one or more of the preamble 1002 or DL ​​data frames 1004-1010. The STA can calculate the baseline transmit power based on index 1 and index 2. The STA can verify the power adjustment parameters carried in one or more of the preamble 1002 or DL ​​data frames 1004-1010 and can increase or decrease the baseline transmit power accordingly. If the STA communicates with the AP during a certain time period, the STA can have recorded transmit power control-related parameters. The STA can weight the historical transmit power control-related parameters and combine them with the instantaneous transmit power obtained from any one or more of the parameters or values ​​received in one or more of the preamble 1002 or DL ​​data frames 1004-1010. The STA can adjust the calculated transmit power according to the transmit bandwidth and antenna settings. The STA can confirm that the transmit power calculated using any publicly available method does not violate the maximum permissible transmit power and transmit power density. Otherwise, the STA may use the maximum permissible transmit power instead.

[0249] After the SIFS time following the transmission, the STA can receive an acknowledgment frame from the AP.

[0250] Now refer to Figure 11 This illustrates the TPC procedure for a UL control frame with UL Clear Transmission (CTS). Figure 11 An exemplary procedure for a UL MU-OFDMA control transmission with power control is illustrated. In this example, the AP can acquire channels from four STAs and can transmit a downlink multi-user request transmission (RTS) 1104. During the SIFS duration following the arrival of the DL MU RTS at the user, the STA can transmit a MUCTS to the AP, shown as UL CTS frames 1106-1112. In one embodiment, each UL CTS 1106-1112 can be transmitted on a separate subframe. In this case, the procedure can be similar to the one described above. Figure 9 The described UL data transmission method. In another implementation, each STA can transmit a combined information RF and a full bandwidth CTS at the receiver. In this case, the AP can request each STA to transmit a portion of its estimated power to prevent the combined CTS from overwhelming the AGC. This portion can be explicitly suggested by the AP or implicitly estimated by the STAs based on the number of STAs in the MU-RTS. For example, for four STAs in the MU-RTS, if two of the estimated STAs do not respond, the transmit power can be scaled by 4 or 2.

[0251] Now refer to Figure 12The diagram illustrates the TPC process for cascading UL / DL MU OFDMA transfers. Figure 12 An exemplary procedure for cascaded UL and DL transmission data with power control is illustrated. In this example, the AP can acquire a channel with four OFDMA resource units. In a DL trigger frame, which can be sent in preamble 1202 or DL ​​data frames 1004-1010, the AP can assign OFDMA resource units 1 to 4 to a specific user and transmit information in them (as DL data frames 1004-1010). During the SIFS duration following the trigger frame, the STA can send ACK frames 1112-1116 and / or ACK and data frames 1118 to the AP using TPC and assignment information in the preamble or user-specific MAC header. Subsequent transmissions by the AP may include a DLACK frame 1120, DL data frames 1122-1124, and a cascaded trigger frame 1126 to the STA. The STA can then send additional ACK frames 1128-1130 and additional UL data 1132-1134 to the AP using the cascaded trigger frame containing additional TPC information. In this case, the AP and STATPC procedures can be similar to those described above for non-cascaded structures.

[0252] Now refer to Figure 13 This illustrates a Transport Opportunity-Based Transmission Program (TPC). In one implementation, the TPC can be applied to a specific TXOP. Within a TXOP, the Network Allocation Vector (NAV) setting 1310 and the TPC information 1312 can be updated.

[0253] In one implementation, AP 1306 can acquire the channel medium using a contention- or scheduling-based method, and the AP can initiate a cascaded TXOP with DL transmission 1302, which can be a DL MU-PPDU sent to multiple users. In DL transmission 1302, TPC information can be carried in the PLCP header, MAC header, and / or broadcast / multicast / unicast trigger frames. In one implementation, AP 1306 can include an open-loop power control index (index 1) in DL transmission 1302. In one implementation, the open-loop power control index (index 1) can be carried in a separate trigger frame. In another implementation, the open-loop power control index (index 1) can be carried in the MAC header of each DL MAC frame in DL transmission 1302.

[0254] AP 1306 may include a power calibration index (index 2) in DL transmission 1302. In one embodiment, the power calibration index (index 2) may be carried in a separate trigger frame. In another embodiment, the power calibration index (index 2) may be carried in the MAC header of each DL MAC frame in DL transmission 1302. This power calibration index (index 2) may be the target link margin or the expected received power on the AP 1306 side. In the following UL MU transmission, one or more expected STA1308s may attempt to reach the AP using the target power level.

[0255] AP 1306 may include user-specific power adjustment parameters in DL transmission 1302. For resource elements assigned to STA 1308 for random access, the power adjustment parameters may be the same across STA 1308. The power adjustment parameters may be the same or different for all receivers at indices 1 and / or 2 in DL transmission 1302 and / or trigger frames. AP 1306 may include any updated TPC report frames discussed above.

[0256] The anticipated STA 1308 can adjust its transmit power for UL MU transmission based on received TPC information. After the SIFS time, AP 1306 can receive a triggered UL PPDU or ULACK / BA from one or more anticipated STA 1308s during UL MU transmission 1314. The one or more anticipated STA 1308s can adjust their transmit power based on the baseline transmit power and the transmit power adjustment value received in the previous DL transmission 1302.

[0257] AP 1306 may cascade one or more DL transmissions 1304 after receiving a UL MU transmission 1314 from one or more intended STAs 1308. AP 1306 may use the cascaded transmissions 1304 to transmit a DL MU-PPDU to another set of STAs 1308. The new set of intended receiving STAs 1308 may be the same as or different from the previous set, or a portion thereof. AP 1306 may or may not update the TPC information in the cascaded DL frames 1304. AP 1306 may include updated power control information, such as index 1, index 2, power adjustment parameters, and / or updated TPC reports to the new set of STAs 1308, in the PLCP header, MAC header, and / or trigger frame. The power control information may be the same as or different from the power control information transmitted in DL transmission 1302. If AP 1306 does not include updated power control information, STA 1308 may reuse the information transmitted in DL transmission 1302. In the cascaded DL frame 1304, AP 1306 can also update the duration information, so that the unexpected STA 1316 can update the NAV setting 1310 accordingly.

[0258] After the SIFS time, the AP can receive a trigger-based UL PPDU or ULACK / BA from STA 1308 in UL transmission 1318. STA 1308 can adjust its transmit power based on the baseline transmit power and the transmit power adjustment value received in the previous cascaded DL transmission 1304. After the SIFS time, AP 1306 can transmit MU BA 1320 to STA 1308.

[0259] Subsequently, AP 1306 can reacquire the channel medium through contention or scheduling. AP 1306 can then initiate a new TXOP 1322. In this TXOP 1322, power control-related information can be carried in the TXOP. In one embodiment, the power control information can be exchanged in a manner similar to the steps in the previously cascaded TXOP 1324. If the power control information is not carried in TXOP 1322, STA 1308 can use, for example, the previous power control information received in the previously cascaded TXOP 1324 to set the UL transmission power.

[0260] Although the features and elements have been described above in specific combinations, those skilled in the art will understand that each feature or element can be used alone or in various combinations with other features and elements. Furthermore, the methods described herein can be implemented in a computer program, software, or firmware incorporated into a computer-readable storage medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted via wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, read-only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor storage devices, magnetic media such as built-in disks and removable disks, magneto-optical media, and optical media (e.g., CD-ROMs and digital multipurpose discs (DVDs)). The processor associated with the software can be used to implement a radio frequency transceiver used in a WTRU, UE, terminal, base station, RNC, or any host.

Claims

1. A station (STA), comprising: antenna; and a processor, which is operatively coupled to the antenna; The processor and the antenna are configured to receive downlink (DL) frames from an access point (AP), the DL frames including in a Media Access Control (MAC) header: a first index indicating open-loop power control parameters and a second index indicating power calibration parameters, wherein the first index indicating the open-loop power control parameters is calculated based on the transmit power used by the AP to transmit the DL frame, and the second index indicating the power calibration parameters is a target link margin or the expected received signal power at the AP, wherein the DL frame is a DL Multi-User Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) MU-PPDU, and the DL frame triggers uplink (UL) multi-user (MU) transmission; The processor and the antenna are also configured to measure the received power of the DL frame; The processor is configured to calculate the downlink path loss of the DL frame based on the first index indicating the open-loop power control parameters and the measured received power of the DL frame. The processor is also configured to determine the STA transmit power based on the calculated downlink path loss and the second index indicating the power calibration parameters; as well as The processor and the antenna are also configured to send an uplink (UL) frame to the AP using the determined STA transmit power as part of a triggered UL MU transmission.

2. The STA according to claim 1, wherein, The processor and the antenna are configured to receive the DL frame and transmit the UL frame during a first transmission opportunity (TXOP).

3. The STA according to claim 1, wherein, The processor and the antenna are also configured to receive individual trigger frames from the AP.

4. The STA of claim 1, wherein the UL frame includes a UL PPDU or a UL ACK / Block ACK (BA).

5. The STA according to claim 1, wherein, The DL frame is one of multiple DL MU-PPDUs sent simultaneously by the AP to the corresponding multiple STAs.

6. The STA of claim 1, wherein the STA is configured as a non-AP STA.

7. A method for use in a station (STA), the method comprising: A downlink (DL) frame is received from an access point (AP), the DL frame including in a Media Access Control (MAC) header: a first index indicating open-loop power control parameters and a second index indicating power calibration parameters, wherein the first index indicating the open-loop power control parameters is calculated based on the transmit power used by the AP to transmit the DL frame, and the second index indicating the power calibration parameters is a target link margin or the expected received signal power at the AP, wherein the DL frame is a DL Multi-User Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) MU-PPDU, and the DL frame triggers uplink (UL) multi-user (MU) transmission; Measure the received power of the DL frame; The downlink path loss of the DL frame is calculated based on the first index indicating the open-loop power control parameters and the measured received power of the DL frame. The STA transmit power is determined based on the calculated downlink path loss and the second index indicating the power calibration parameters; and Sending a UL frame to the AP using the determined STA transmit power as part of the triggered UL MU transmission.

8. The method according to claim 7, wherein, During the first transmission opportunity (TXOP), the DL frame is received and the UL frame is transmitted.

9. The method according to claim 7, further comprising: Receive individual trigger frames from the AP.

10. The method of claim 7, wherein, The UL frame includes a UL PPDU or a UL ACK / Block ACK (BA).

11. The method of claim 7, wherein, The DL frame is one of multiple DL MU-PPDUs that are simultaneously transmitted by the AP to the corresponding multiple STAs.

12. The method according to claim 7, wherein, The STA is a non-AP STA.

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