Ever since I upgraded my Galaxy Note 8 to Android 4.2.2 I have been unhappy with the battery life. The most concerning issue is that with the Note 8 sitting unused battery life was decreasing by one percent every six to eight minutes. A device sitting unused ought to be able to go at least a few days between charges, but at that rate the Note 8 will be dead in about 7 to 9 hours.
The Solution: Assign A Static IP Address
The solution for me was to configure my Galaxy Note 8 to use a static IP address when it connects to my home network. While I provide some instructions below for how to configure the Note 8 to use a static IP address, the process requires some knowledge of how wireless access points work.
If you are not familiar with the settings of your home wireless access point, you will want to find someone who can help you with these changes. With so many different brands of access points, I cannot provide instructions for how to use the settings of each to obtain the information need to make this configuration change.
The Problem: wlan_rx_awake Kept My Note 8 Constantly Awake
BetterBatteryStats showed the Note 8 to be awake almost the entire time it was unplugged, instead of of being in Deep Sleep. The following screenshot shows a better depiction of what you should get, with the device in deep sleep at least 75% of the time while it is not being used.
The problem, according to BetterBatteryStates was wlan_rx_awake, which was keeping my Note 8 awake almost the entire time. After some research, I learned that wlan_rx_awake is caused due to the device constantly needing to respond to DHCP requests on the wireless network.
Dynamic Host Configuration Protocol (DHCP)
Like most people, have I a home wireless network and use Dynamic Host Configuration Protocol, DHCP, to automatically assign IP addresses to the devices that connect to the network. If you have a home wireless LAN, most likely you are using DHCP as that is the default configuration for all of the home wireless access points.
DHCP is also used at most businesses as it greatly simplifies administration of local area networks. The alternative is to assign an address, providing what is called a static IP address, by manually changing the configuration of the device.
If a device is configured to use DHCP, each time it connects to a network it makes a request for an IP address. DHCP server software, which is available in almost all wireless access points, provides an IP address to devices when they connect to the network.
DHCP assigns IP addresses for a specified period of time, after which the address expires and the device has to request a new address. You can change the length of time before an address expires, and on my network I have addresses set to expire after one day.
Normally, after 24 hours passes, the devices on my network make a new DHCP request for an address. DHCP also normally keeps assigning the same address to the same devices as long as it maintains a connection. Something has been causing my Note 8 to constantly request an update to the address regardless of how I have the router configured.
To solve the problem I first upgraded the firmware on my access point after I discovered it was more than a year old, but that did not solve the problem. I didn’t expect it to as the same router was in use before the 4.2.2 upgrade and I didn’t see this problem.
- Some message boards posts that I have read about this problem suggest the issue has to do with the wireless router and not the device. In my case, however, I am seeing the problem when my Note 8 connects to my home network and when it connects to the wireless LAN at the office. Odds are the problem is with the Note 8 and not with both networks.
My next step was to configure the DHCP server on the access point to assign a specific IP address to the Note 8. Normally, addresses are randomly assigned from a pool so there is a possibility for the address to change between reboots. If you need a device to have the same address you can configure DHCP to do so by associating an IP address to the MAC address of the device. Unfortunately, this too, did not solve my problem.
Assigning A Static IP Address To A Galaxy Note 8
The final step to solving the problem was assigning a static IP address to my Note 8. To do this I had to go in to the Wi-Fi setting on the Note 8, tap and hold on the entry for my home network and select Forget, then tap Add Wi-Fi network, and complete the dialog shown in this screen shot:
You need to tap the Show Advanced Options check box to expose the Proxy Settings and IP Settings fields. Leave Proxy Settings to None, change IP Settings to Static, which exposes the IP Address field, and then enter the IP Address and Gateway addresses in the appropriate fields of the dialog box. The fields have an example of an IP address but you need to enter the information as those are just examples and not actual values.
The DHCP servers for most home wireless networks assign addresses using a 192.168.1.x network, with 18.104.22.168 usually assigned to the wireless access point, which also known as the Gateway to the public Internet. You need to entire the IP address for your access point in the Gateway field of the dialog box shown above.
You will find in the access point’s settings the number of devices DHCP is configured to support and the range of addresses it uses to assign to those devices. For example, on my network, DHCP assigns addresses in the range of 192.168.1.100 to 192.168.1.149, so you do not want to use an address in that range for the static IP address of your device. If your home network is like mine, you have plenty of addresses available to use starting with 192.168.1.2 up to 192.168.1.99.
You also need to provide DNS server addresses in the DNS1 and DNS2 fields, but you can use the 22.214.171.124 and 126.96.36.199 addresses provided as examples, those are the addresses to Google’s DNS servers that you can use.
After I configured my Galaxy Note 8 to use a static IP address, the battery discharging speed improved dramatically up to ~20 minutes per one percent of life, or put differently, I should now be able to get nearly two full days between charges, assuming normal usage. If you don’t seem to get as much battery life out of your device as you would expect, you may want to try changing to a static IP address to see if it makes an improvement.