Admob banner overlapping

Question

This is my code but my banner-ad renders in front of the main activity which creates issues with admob policy

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:ads="http://schemas.android.com/apk/res-auto">

<ImageView
    android:id="@+id/background_image"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:scaleType="centerCrop" />

<FrameLayout
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

</FrameLayout>

<RelativeLayout
    android:id="@+id/popup_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
</RelativeLayout>

<RelativeLayout  android:id="@+id/ad_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom">

    <com.google.android.gms.ads.AdView
        android:id="@+id/adView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        ads:adSize="BANNER"
        ads:adUnitId="ca-app-pub-3940256099942544/9214589741" />

</RelativeLayout>

I have created a container with relative layout and set its gravity to bottom what i would like to achieve is to have the background image and fragment activity render on top of the banner ad