|
| 1 | +.. _siwx917_wifi_features: |
| 2 | + |
| 3 | +SiWx917 Wi-Fi Features (Alpha) |
| 4 | +############################## |
| 5 | + |
| 6 | +Overview |
| 7 | +======== |
| 8 | + |
| 9 | +This document provides an overview of the 917 Wi-Fi module's capabilities and |
| 10 | +features, focusing on its STA and Soft-AP modes. |
| 11 | + |
| 12 | + |
| 13 | +STA Mode Features |
| 14 | +================= |
| 15 | + |
| 16 | +The STA (Station) mode of the 917 Wi-Fi module provides robust functionality |
| 17 | +for connecting to wireless networks as a client. Below are the key features: |
| 18 | + |
| 19 | + |
| 20 | +Scan |
| 21 | +---- |
| 22 | + |
| 23 | +The STA mode supports network scanning to identify available access points: |
| 24 | + |
| 25 | + - **Active Scanning**: Actively probes for nearby networks. |
| 26 | + - **Passive Scanning**: Listens for beacon frames to discover networks. |
| 27 | + - **Background (BG) Scanning**: Supports background scanning to identify |
| 28 | + better access points without interrupting the active connection. |
| 29 | + |
| 30 | +The module supports up to **11 scan results** at a time, ensuring efficient |
| 31 | +discovery of nearby access points. |
| 32 | + |
| 33 | +The module supports only one SSID that can be specified for SSID filtering. |
| 34 | + |
| 35 | +Active and Passive scanning are performed when the device is not in associated |
| 36 | +state. |
| 37 | + |
| 38 | +BG Scanning is performed when the device is in associated state. |
| 39 | + |
| 40 | +If channel is not provided, the device will scan all the valid channels. |
| 41 | + |
| 42 | +The default active dwell time is 100 ms. |
| 43 | + |
| 44 | +The default passive dwell time is 400 ms. |
| 45 | + |
| 46 | + |
| 47 | +Security |
| 48 | +-------- |
| 49 | + |
| 50 | +The module incorporates advanced security measures to ensure a safe and |
| 51 | +reliable connection. It supports the following security modes: |
| 52 | + |
| 53 | + - **Open**: No encryption, suitable for unsecured networks. |
| 54 | + - **WPA (Wi-Fi Protected Access)**: Provides improved security over WEP. |
| 55 | + - **WPA2 (Wi-Fi Protected Access II)**: Industry-standard encryption for |
| 56 | + most networks. |
| 57 | + - **WPA3 (Wi-Fi Protected Access III)**: Enhanced encryption and protection |
| 58 | + against modern threats. |
| 59 | + - **WPA2-SHA256**: Enhanced WPA2 security using SHA256 for improved |
| 60 | + cryptographic strength. |
| 61 | + - **WPA3 Transition Mode (WPA2+WPA3)**: Ensures compatibility with networks |
| 62 | + that use both WPA2 and WPA3 security standards. |
| 63 | + |
| 64 | +These modes ensure that the module can connect securely to a wide range of |
| 65 | +networks while maintaining strong data protection. |
| 66 | + |
| 67 | + |
| 68 | +Link Modes |
| 69 | +---------- |
| 70 | + |
| 71 | +To ensure compatibility with diverse networks, the module supports multiple |
| 72 | +Wi-Fi link modes: |
| 73 | + |
| 74 | + - **802.11b (Wi-Fi 0 and Wi-Fi 1)**: Legacy mode with speeds up to 11 Mbps. |
| 75 | + - **802.11g (Wi-Fi 3)**: Enhanced performance up to 54 Mbps. |
| 76 | + - **802.11n (Wi-Fi 4)**: High throughput with MIMO technology. |
| 77 | + - **802.11ax (Wi-Fi 6)**: Next-generation efficiency, capacity, and |
| 78 | + performance. |
| 79 | + |
| 80 | + |
| 81 | +Power Save |
| 82 | +---------- |
| 83 | + |
| 84 | +The module implements power-saving mechanisms to optimize energy consumption. |
| 85 | + |
| 86 | +It supports the following legacy power-saving modes: |
| 87 | + |
| 88 | + - **DTIM (Delivery Traffic Indication Message) Based**: Reduces power |
| 89 | + consumption by using DTIM intervals to wake up only when buffered data is |
| 90 | + available at the access point. |
| 91 | + - **Listen Interval Based**: Allows the module to wake up periodically based |
| 92 | + on a defined listen interval to check for traffic. The Listen Interval |
| 93 | + will be in units of Beacon Interval. |
| 94 | + |
| 95 | +The device supports (Power save) Listen Interval ranging from 100 ms - 1000 ms. |
| 96 | +Accordingly, the Listen Interval needs to be configured in units of |
| 97 | +Beacon Interval. If the Listen Interval is configured more than 1000 ms, then |
| 98 | +it takes the value as 1000 ms. The Listen Interval based wakeup will take |
| 99 | +effect once the device is in connected state. If the Listen Interval is set to |
| 100 | +zero, the driver will automatically switch to DTIM wakeup. If power save is |
| 101 | +disabled by firmware than driver will take the previously configured |
| 102 | +Listen Interval when it is enabled. |
| 103 | + |
| 104 | +This (Power save) Listen Interval shall be less than the Listen Interval |
| 105 | +advertised in (Re)Association Request frame. |
| 106 | + |
| 107 | +It also supports the below modes to retrieve buffered packets: |
| 108 | + |
| 109 | + - **PS-Poll (Power Save Polling)**: Enables the device to retrieve buffered |
| 110 | + packets from the access point when it has entered power save mode. |
| 111 | + - **QoS Null Data**: Allows the device to send QoS Null frames to retrieve |
| 112 | + buffered packets from the access point in a power-efficient manner. |
| 113 | + |
| 114 | +The device enables its proprietary mode Enhanced Max PSP feature to retrieve |
| 115 | +buffered packets by default for improved performance. |
| 116 | + |
| 117 | +If this feature is disabled through disabling the config flag |
| 118 | +``CONFIG_WIFI_SILABS_SIWX91X_ENHANCED_MAX_PSP``, then QoS Null frame gets |
| 119 | +enabled. Both QoS Null frame and Enhanced Max PSP are mutually exclusive. |
| 120 | + |
| 121 | +After disconnection, PS gets disabled, thus, PS needs to be enabled again for |
| 122 | +new connection, if required. |
| 123 | + |
| 124 | +The Monitor Interval is defined as the time from the last packet received |
| 125 | +(except ACK). If there is no packet received till this interval, then the |
| 126 | +device goes to sleep. The default value of Monitor Interval is 50 ms if 0 is |
| 127 | +configured. This is used for QoS Null Data or Enhanced Max PSP. The device |
| 128 | +supports maximum value of Monitor Interval as 1000 ms. |
| 129 | + |
| 130 | +Currently, ``timeout_ms`` is not supported in the device. |
| 131 | + |
| 132 | + |
| 133 | +Management Frame Protection |
| 134 | +--------------------------- |
| 135 | + |
| 136 | +Support for **802.11w** ensures protection for management frames, safeguarding |
| 137 | +against: |
| 138 | + |
| 139 | + - Deauthentication attacks. |
| 140 | + - Disassociation attacks. |
| 141 | + |
| 142 | +802.11w is enabled by default. |
| 143 | + |
| 144 | +**Recommended MFP Values for different security modes:** |
| 145 | + |
| 146 | + +---------------+-------------+-------------+--------------+ |
| 147 | + | Security Mode | MFP Disable | MFP Capable | MFP Required | |
| 148 | + +===============+=============+=============+==============+ |
| 149 | + | Open | Yes | | | |
| 150 | + +---------------+-------------+-------------+--------------+ |
| 151 | + | WPA | Yes | | | |
| 152 | + +---------------+-------------+-------------+--------------+ |
| 153 | + | WPA + WPA2 | | Yes | Optional | |
| 154 | + +---------------+-------------+-------------+--------------+ |
| 155 | + | WPA2 | | Yes | Optional | |
| 156 | + +---------------+-------------+-------------+--------------+ |
| 157 | + | WPA2 + WPA3 | | Yes | No | |
| 158 | + +---------------+-------------+-------------+--------------+ |
| 159 | + | WPA3 | | Yes | Yes | |
| 160 | + +---------------+-------------+-------------+--------------+ |
| 161 | + |
| 162 | + |
| 163 | +BG Scan and Roaming |
| 164 | +------------------- |
| 165 | + |
| 166 | +Roaming enables a Wi-Fi STA (Station) to seamlessly transition from one |
| 167 | +Access Point (AP) to another within the same network without losing its |
| 168 | +connection. This ensures uninterrupted connectivity as the STA moves across |
| 169 | +different AP coverage areas. |
| 170 | + |
| 171 | +The device support **Legacy Roaming**, which comprises the following procedures: |
| 172 | + |
| 173 | + 1. **Background (BG) Scan**: |
| 174 | + |
| 175 | + - A standard scanning procedure executed while the STA remains connected |
| 176 | + to the network. |
| 177 | + - Triggered when the Received Signal Strength Indicator (RSSI) falls |
| 178 | + below a predefined threshold. |
| 179 | + |
| 180 | + 2. **Roaming**: |
| 181 | + |
| 182 | + - Initiated when the RSSI crosses the threshold and a roaming hysteresis |
| 183 | + condition is met. |
| 184 | + - The roaming process can be carried out using either an |
| 185 | + **NDP (Null Data Packet)** or a **Deauthentication frame**. The default |
| 186 | + configuration is to use NDP. The configuration can be changed using |
| 187 | + Kconfig ``CONFIG_WIFI_SILABS_SIWX91X_ROAMING_USE_DEAUTH`` to use a |
| 188 | + deauthentication frame for Roaming. |
| 189 | + |
| 190 | + |
| 191 | +**Challenges**: |
| 192 | + |
| 193 | + - The **Zephyr API** does not currently provide an API for Legacy Roaming. |
| 194 | + While APIs for **802.11r roaming** are defined, they do not apply to |
| 195 | + Legacy Roaming. |
| 196 | + |
| 197 | +**Current Design**: |
| 198 | + |
| 199 | + - **BG Scan**: Performed using the Scan API. |
| 200 | + |
| 201 | + - **Roaming Configuration**: Configured during the first BG Scan. Roaming |
| 202 | + parameters are managed through **Kconfig** options. |
| 203 | + |
| 204 | +Roaming is enabled by default, but BG Scan needs to be performed to initiate |
| 205 | +and configure the Roaming parameters. Roaming can be disabled by disabling the |
| 206 | +config flag ``WIFI_SILABS_SIWX91X_ENABLE_ROAMING``. |
| 207 | + |
| 208 | +BG Scan stops when the STA gets disconnected. This BG Scan command again needs |
| 209 | +to be given to enable BG Scan and Roaming. |
| 210 | + |
| 211 | +The device support multi-probe in BG Scan where it can also scan APs with |
| 212 | +different SSID. This configuration can be disabled using Kconfig. |
| 213 | + |
| 214 | + |
| 215 | +Target Wake Time (TWT) |
| 216 | +---------------------- |
| 217 | + |
| 218 | +The module supports **Individual Target Wake Time (TWT)** in compliance with |
| 219 | +Wi-Fi 6 standards: |
| 220 | + |
| 221 | + - **Individual TWT**: Allows the module to negotiate wake times with the |
| 222 | + access point, optimizing power consumption for the device. It supports |
| 223 | + only as a requester. |
| 224 | + - Does not support broadcast TWT. |
| 225 | + |
| 226 | +This feature is ideal for IoT devices requiring periodic connectivity with |
| 227 | +minimal energy use. |
| 228 | + |
| 229 | +The device does not support Explicit TWT. It does not support |
| 230 | +TWT Information element. |
| 231 | + |
| 232 | +The device does not support TWT quick setup. It does not support configuring |
| 233 | +parameters like TWT interval, TWT wake ahead duration and dialog token. |
| 234 | + |
| 235 | + |
| 236 | +Bugs and Limitations |
| 237 | +-------------------- |
| 238 | + |
| 239 | + - The default configuration complies with US regulatory domain. Thus, it |
| 240 | + supports Channels 1-11 only, ensuring operation within permitted |
| 241 | + frequencies for the US region. |
| 242 | + - For WPA3 (SAE), our device has a limitation of 64 characters on the |
| 243 | + password. |
| 244 | + - EAP security modes are not supported. |
| 245 | + - The link mode in Wi-Fi status is always ``WIFI_LINK_MODE_UNKNOWN``. |
| 246 | + - The device supports bandwidth of 20 MHz only and 1 spatial stream. |
| 247 | + - 802.11r is not supported. |
| 248 | + - WMM power save mode is not supported. |
| 249 | + |
| 250 | + |
| 251 | +Soft-AP Mode Features |
| 252 | +===================== |
| 253 | + |
| 254 | +In Soft-AP (Software Access Point) mode, the 917 Wi-Fi module can act as an |
| 255 | +access point, allowing other devices to connect to it. Below are the key |
| 256 | +features: |
| 257 | + |
| 258 | + |
| 259 | +Security |
| 260 | +-------- |
| 261 | + |
| 262 | +The module provides secure connections for devices connecting to the Soft-AP. |
| 263 | +It supports the following security modes: |
| 264 | + |
| 265 | + - **Open**: No encryption, suitable for unsecured networks. |
| 266 | + - **WPA (Wi-Fi Protected Access)**: Provides improved security over WEP. |
| 267 | + - **WPA2 (Wi-Fi Protected Access II)**: Industry-standard encryption for |
| 268 | + most networks. |
| 269 | + - **Mixed Mode (WPA+WPA2)**: Ensures compatibility with networks that use |
| 270 | + both WPA and WPA2 security standards. |
| 271 | + |
| 272 | +These modes allow flexible configurations for devices connecting to the Soft-AP. |
| 273 | + |
| 274 | + |
| 275 | +Link Modes |
| 276 | +---------- |
| 277 | + |
| 278 | +Soft-AP mode supports the following link modes: |
| 279 | + |
| 280 | + - **802.11b (Wi-Fi 0 and Wi-Fi 1)**: Legacy mode for basic connectivity. |
| 281 | + - **802.11g (Wi-Fi 3)**: Enhanced speeds for modern devices. |
| 282 | + - **802.11n (Wi-Fi 4)**: High-speed connectivity for demanding applications. |
| 283 | + |
| 284 | + |
| 285 | +Hidden SSID |
| 286 | +----------- |
| 287 | + |
| 288 | +Allows the network name (SSID) to be concealed from broadcasting. This enhances |
| 289 | +privacy by preventing the SSID from being visible to unauthorized users. |
| 290 | + |
| 291 | + |
| 292 | +Bugs and Limitations |
| 293 | +-------------------- |
| 294 | + |
| 295 | + - The default configuration complies with US regulatory domain. Thus, it |
| 296 | + supports Channels 1-11 only, ensuring operation within permitted |
| 297 | + frequencies for the US region. |
| 298 | + - The link mode in Wi-Fi status is always ``WIFI_LINK_MODE_UNKNOWN``. |
| 299 | + - The device supports bandwidth of 20 MHz only and 1 spatial stream. |
| 300 | + - Although STA and BLE can coexist simultaneously, AP and BLE cannot operate |
| 301 | + together. |
0 commit comments