{"id":901,"date":"2010-08-16T15:50:20","date_gmt":"2010-08-16T08:50:20","guid":{"rendered":"http:\/\/deepquest.code511.com\/blog\/?p=901"},"modified":"2010-08-16T15:50:20","modified_gmt":"2010-08-16T08:50:20","slug":"install-a-virtual-gsm-relay-bts-on-android","status":"publish","type":"post","link":"https:\/\/deepquest.code511.com\/blog\/2010\/08\/install-a-virtual-gsm-relay-bts-on-android\/","title":{"rendered":"Install a virtual GSM relay (BTS) on Android"},"content":{"rendered":"

With minimal work it\u2019s possible to get\u00a0gnuradio<\/a> andOpenBTS<\/a> working on the ARMEL architecture used on the Droid, allowing my Droid to act as a base station to which handsets can connect; the Droid then connects calls using an on-board Asterisk server and routes them to the PSTN via SIP over Verizon\u2019s 3G network.<\/p>\n

The quick version: I can provide voice and SMS connectivity to local GSM handsets using nothing but a Droid and a USRP.<\/p>\n

A quick log of what you\u2019ll need to replicate this. This is from memory so I may have missed something; fortunately there\u2019s an easier way that I\u2019ll come back to.<\/p>\n

– Root the Droid and install\u00a0Sholes Mod<\/a>.
\n– Mount your SD card in a desktop machine and create an EXT3 partition. I shrank the FAT32 partition but left it otherwise intact, this is probably a good idea if you want to still take pictures.
\n– debootstrap into the new ext3 partition, bearing in mind the new architecture (use the two-stage debootstrap with \u2013foreign)
\n– Put the SD card back in the Droid, and mount the EXT3 partition (you\u2019ll probably need to manually insmod the ext3 and jbd modules)
\n– \u201cmount -o bind\u201d all of the system filesystems into the mounted EXT3 environment (including \/dev, \/dev\/pts, and \/sys)
\n– Mount usbfs in the mounted filesystem at \/proc\/bus\/usb (if you don\u2019t it won\u2019t find the USRP)
\n– chroot into the new Debian environment, and debootstrap \u2013second-stage
\n– Go get dinner \u2013 it\u2019ll be a while
\n– Install all the usual dependancies for building gnuradio (if you can\u2019t figure this out on your own you\u2019re in the wrong place!)
\n– Configure gnuradio with .\/configure \u2013disable-all-components \u2013enable-usrp \u2013enable-omnithread \u2013enable-mblock \u2013enable-pmt
\n– Patch for 52MHz clock (I highly doubt that Droid can handle the stock 64MHz clock)
\n–\u00a0Patch the gnuradio makefiles for ARMEL<\/a>
\n– Build gnuradio (again, it\u2019ll be a while)
\n– Install libosip2-3.3.0 from source (the Debian package is out of date)
\n– Download and .\/configure the openbts source, but don\u2019t build it
\n– Apply the same makefile patch in Transceiver\/ and Transceiver52M\/ (or you\u2019ll get the same build error)
\n– Build OpenBTS
\n– Install Asterisk (from the debian packages is fine)
\n– Configure as you wish, then connect the USRP (via a powered hub) in Host mode and have fun!<\/p>\n

The easier way that I mentioned before would be for me to just zip up an image of my SD card and slap it on a fileserver somewhere public \u2013 I\u2019ll also include some scripts to mount it and start everything up correctly. Give me a few days to clean it up and watch on Twitter for the link, it should be as simple as dropping 2 files on the SD card and then running one of them as root.<\/p>\n

I\u2019ll also post video of the Droid connecting a call (that sounds far less cool than it should) at some point, I\u2019m also considering running a workshop on all of this if there\u2019s any interest\u2026?<\/p>\n

credit: Chris Paget<\/p>\n","protected":false},"excerpt":{"rendered":"

With minimal work it\u2019s possible to get\u00a0gnuradio andOpenBTS working on the ARMEL architecture used on the Droid, allowing my Droid to act as a base station to which handsets can…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[108,85],"tags":[],"class_list":["post-901","post","type-post","status-publish","format-standard","hentry","category-android-2","category-smartphone"],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p4bBYZ-ex","jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/901","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/comments?post=901"}],"version-history":[{"count":2,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/901\/revisions"}],"predecessor-version":[{"id":904,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/posts\/901\/revisions\/904"}],"wp:attachment":[{"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/media?parent=901"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/categories?post=901"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deepquest.code511.com\/blog\/wp-json\/wp\/v2\/tags?post=901"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}