There is a more reliable way: Use USB Tethering instead of WiFi on your android phone. Depending on what exactly you're planning to do, it might get complicated though.
The advantage of USB tethering over WiFi is: no configuration of WiFi SSID/password is needed, which is especially difficult on the Pi if you don't have a keyboard and HDMI screen with you. Just plug-in the USB cable, go to Settings-Tethering and enable "USB Tethering". This works without a SIM card in your phone.
The android phone usually gets the IP
192.168.42.129 and the connected device (your Raspberry Pi) will get a some IP assigned by its DHCP. You might need to use nmap to find the IP address of your Pi:
nmap -p 22 192.168.42.1-255 | grep -B3 -A1 open
Once you have the IP of your Pi, you could easily connect to its sshd using your android phone and a ssh client (i.e. an ssh app from the Google Play Store).
On the Pi, the network interface created by the USB tethering will have the name
USB tethering has also 1 disadvantage: you can only connect 2 devices with each other. So if you want to connect your laptop to the same LAN, it becomes tricky:
On android (tested with v5.1) you can enable both, USB tethering and a WiFi hotspot at the same time. Just enable both switches in Settings-Tethering. However, you will end up with 2 different LAN networks. i.e.
192.168.43.* -- devices on each of these LAN will not be able to talk to each other, but only to their gateway (your android phone).
I have a chroot Linux installed on my android (
Linux Deploy freely available in the Google Play Store, these days you might be able to make it run without a rooted android using p-root). So I can easily connect to the Linux-Deploy-ssh on my android from my laptop (using the WiFi hotspot) and from that ssh session, I can login to the Pi via its sshd again.
Using my laptop and 2 ssh connections, I can now make changes to the Pi's config, deploy code and update software etc. It's a bit involved, but it works fine.
In my experience, USB tethering is more reliable than WiFi, especially for devices that are supposed to run forever. Also, there is pretty much no latency compared to an overloaded WiFi environment.