Overview

Bluetooth Low Energy (BLE) and Wi-Fi operate in the same band, and in some devices, share a single radio. This can cause data transmission on one interface to interfere with the other. Such interference can impact the performance of both Wi-Fi and BLE. In order to avoid such interference, coexistence (coex) configurations and algorithms are introduced in the underlying WLAN and BT stacks. These configurations can be tuned from the application to test and improve the performance of the underlying Wi-Fi and BLE traffic when they are operated simultaneously.

This library provides an API that allows the user to configure the coex parameters for WLAN and BLE.

Features and Functionality

• Supports Wi-Fi BT coex configuration based on BLE Scan priority. User can set the LE Scan priority, with one of three options - high, medium and low. Based on the priority, the different LE scan parameters are configured.

Supported Framework(s)

• AnyCloud Framework: AnyCloud is a FreeRTOS-based solution. Smart Coex library uses the wifi-connection-manager library for Wi-Fi network connectivity functions, and bluetooth-freertos for BLE.

Supported Platform(s)

AnyCloud

• PSoC 62S2 Wi-Fi BT Pioneer Kit (CY8CKIT-062S2-43012)

Dependent Libraries

AnyCloud

• Wi-Fi Connection Manager
• Connectivity Utilities Library
• bluetooth-freertos

Quick Start

A set of pre-defined configuration files have been bundled with the wifi-mw-core library for FreeRTOS, lwIP, and mbed TLS. Review the configuration and make the required adjustments. See the "Quick Start" section in README.md.

• Define the following COMPONENTS in the application's Makefile for the Smart Coex library.

  COMPONENTS=FREERTOS MBEDTLS LWIP WCM WICED_BLE

• Add the following compiler directives to the DEFINES section in the application's Makefile:

  DEFINES+=CYBSP_WIFI_CAPABLE

• By default, log messages are disabled by the Smart Coex library. To enable log messages, the application must perform the following:
  • Add the ENABLE_SMARTCOEX_LOGS macro to the DEFINES in the code example's Makefile. The Makefile entry would look like this:

    DEFINES+=ENABLE_SMARTCOEX_LOGS

  • Call the cy_log_init() function provided by the cy-log module. cy-log is part of the connectivity-utilities library. See connectivity-utilities library API documentation for cy-log details.

Code Snippets

This section provides code snippet for this library on AnyCloud framework.

Smart Coex Config on AnyCloud

The following snippet demonstrates the usage of the Smart Coex library API, in AnyCloud, to configure the WiFi and BT parameters for operating in coexistence.

#include "cy_smartcoex.h"
#include "cy_wcm.h"

/******************************************************
 *                      Macros
 ******************************************************/

#define APP_INFO( x )                        printf x
#define APP_DEBUG( x )                       //printf x
#define APP_ERROR( x )                       printf x

/* BT scan priority */
#ifndef BT_CONFIG_SCAN_PRIORITY
#define BT_CONFIG_SCAN_PRIORITY  CY_SMARTCOEX_LESCAN_PRIORITY_MEDIUM
#endif

/* BT scan interval */
#ifndef BT_CONFIG_SCAN_INTERVAL
#define BT_CONFIG_SCAN_INTERVAL  2
#endif

/* BT scan window */
#ifndef BT_CONFIG_SCAN_WINDOW
#define BT_CONFIG_SCAN_WINDOW    1
#endif

/************************************************************
 *                       Global Variables                   *
 ************************************************************/
/* Smart Coex configuration parameters */
static cy_smartcoex_wifi_config_t wifi_config;
static cy_smartcoex_bt_config_t   bt_config;


int bt_on()
{
    // Add BT stack initialization logic here.

    return 0;
}

cy_rslt_t smartcoex_config()
{
    cy_rslt_t res;
    int result;
    cy_wcm_config_t config;

    // Initialize wcm.
    config.interface = CY_WCM_INTERFACE_TYPE_STA;
    res = cy_wcm_init(&config);
    if(res != CY_RSLT_SUCCESS)
    {
        APP_ERROR(("cy_wcm_init failed with error:[0x%X]\n", (unsigned int)res));
        return res;
    }

    // Initialize the BT stack.
    result = bt_on();
    if(result == -1)
    {
        APP_ERROR(("Failed to initialize BT stack.\n"));
        return CY_RSLT_MW_ERROR;
    }

    // Set up Smart Coex configuration.
    wifi_config.interface = CY_SMARTCOEX_INTERFACE_TYPE_STA;

    bt_config.scan_priority = BT_CONFIG_SCAN_PRIORITY;
    bt_config.scan_int = BT_CONFIG_SCAN_INTERVAL;
    bt_config.scan_win = BT_CONFIG_SCAN_WINDOW;
    bt_config.btcoex_cb = &btcoex_callback;

    // Call the Smart Coex API.
    res = cy_smartcoex_config(&wifi_config, &bt_config);
    if(res != CY_RSLT_SUCCESS)
    {
        APP_ERROR(("cy_smartcoex_config failed with error:0x%X\n", (unsigned int)res));
        return res;
    }
    APP_INFO(("smart coex config completed.\n"));

}