dataset selects a channel from channel 11 to 24
Many Thread radio chips need to reduce their transmit power on edge
channels to pass regulatory RF certification. This CL restrcits the
dataset to select a channel from channel 11 to 24.
Bug: b/331708479
Test: atest ThreadNetworkUnitTests
Change-Id: I758c9f33629a0cafcc39bb9fde0ad45ab2699db8
diff --git a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
index 63cd574..6b88787 100644
--- a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
+++ b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
@@ -165,6 +165,9 @@
// Note that this regex allows "XX:XX-XX" as well but we don't need to be a strict checker
private static final String OUI_REGEX = "^([0-9A-Fa-f]{2}[:-]?){2}([0-9A-Fa-f]{2})$";
+ // The channel mask that indicates all channels from channel 11 to channel 24
+ private static final int CHANNEL_MASK_11_TO_24 = 0x1FFF800;
+
// Below member fields can be accessed from both the binder and handler threads
private final Context mContext;
@@ -826,6 +829,14 @@
private static int selectChannel(
int supportedChannelMask, int preferredChannelMask, Random random) {
+ // Due to radio hardware performance reasons, many Thread radio chips need to reduce their
+ // transmit power on edge channels to pass regulatory RF certification. Thread edge channel
+ // 25 and 26 are not preferred here.
+ //
+ // If users want to use channel 25 or 26, they can change the channel via the method
+ // ActiveOperationalDataset.Builder(activeOperationalDataset).setChannel(channel).build().
+ preferredChannelMask = preferredChannelMask & CHANNEL_MASK_11_TO_24;
+
// If the preferred channel mask is not empty, select a random channel from it, otherwise
// choose one from the supported channel mask.
preferredChannelMask = preferredChannelMask & supportedChannelMask;
diff --git a/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java b/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
index 85b6873..493058f 100644
--- a/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
+++ b/thread/tests/unit/src/com/android/server/thread/ThreadNetworkControllerServiceTest.java
@@ -115,7 +115,11 @@
private static final String DEFAULT_NETWORK_NAME = "thread-wpan0";
private static final int OT_ERROR_NONE = 0;
private static final int DEFAULT_SUPPORTED_CHANNEL_MASK = 0x07FFF800; // from channel 11 to 26
- private static final int DEFAULT_PREFERRED_CHANNEL_MASK = 0x00000800; // channel 11
+
+ // The DEFAULT_PREFERRED_CHANNEL_MASK is the ot-daemon preferred channel mask. Channel 25 and
+ // 26 are not preferred by dataset. The ThreadNetworkControllerService will only select channel
+ // 11 when it creates randomized dataset.
+ private static final int DEFAULT_PREFERRED_CHANNEL_MASK = 0x06000800; // channel 11, 25 and 26
private static final int DEFAULT_SELECTED_CHANNEL = 11;
private static final byte[] DEFAULT_SUPPORTED_CHANNEL_MASK_ARRAY = base16().decode("001FFFE0");