FreeCalypso > hg > freecalypso-citrine

annotate doc/TCH-special-feature @ 28:cb00b90edaff

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
documentation write-ups imported from freecalypso-sw and updated for Citrine
author Mychaela Falconia <falcon@freecalypso.org>
date Sun, 12 Jun 2016 18:28:35 +0000
parents
children 3362a76ab432
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
28
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
1 FreeCalypso Citrine firmware implements an optional special feature (needs to be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
2 explicitly enabled at compile time) which we call TCH rerouting. When this
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
3 feature is enabled, it applies the following special handling to GSM voice
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 traffic channels (TCH):
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 * All downlink TCH bits passing from the channel decoder to the vocoder block
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7 (260 bits every 20 ms with the original FR codec) can be non-invasively
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 intercepted and forwarded to the external host connected to the RVTMUX serial
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 interface;
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
11 * Using the same serial interface, the external host can supply substitute
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
12 uplink TCH bits which will be transmitted in the place of the built-in
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 vocoder output, i.e., the latter can be effectively suppressed.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 In order to use this feature, you need to compile our firmware in the voice+SMS
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
16 pseudo-modem configuration, i.e., the configuration in which the fw expects to
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
17 be controlled via AT commands wrapped in the RVTMUX binary packet serial
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
18 interface. You can use a target GSM device that has just one accessible serial
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 port (Mot C1xx and Pirelli DP-L10) or one that has two Calypso UARTs (Openmoko
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20 GTA02 or our future FCDEV3B), but in the latter case you will be using only one
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 UART - whichever one you have configured to be RVTMUX.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
22
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
23 Whatever system you are building that will act as the source and sink for TCH
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 bits will need to interface to the FreeCalypso GSM device via a serial port in
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
25 the RVTMUX binary packet format. Your system will need to send RVTMUX packets
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
26 with AT commands inside them in order to command the FC GSM device to register
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 with the network and to dial and/or answer calls, and you will need to send
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28 RVTMUX packets of a different kind in order to supply the uplink TCH bits
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 during calls. In the other direction, your system will receive responses to
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
30 the AT commands you send, asynchronous notifications of incoming calls and SMS,
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
31 downlink TCH bits and various debug trace output from our FreeCalypso firmware.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 The last part (debug trace output) can be simply ignored and discarded if you
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33 wish, but we strongly recommend that you provide a way to view and/or log it
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 for debugging purposes.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 Please see the RVTMUX document in the FreeCalypso host tools package for general
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 background information regarding the RVTMUX binary packet interface; this
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
38 document should be considered required reading for anyone interested in working
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
39 with the TCH rerouting special feature.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
40
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
41 All packets transferred over the RVTMUX interface begin and end with 0x02. If
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
42 a payload byte within a packet equals 0x02 or 0x10, it needs to be prepended
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
43 with 0x10 as a transparency escape; all other payload bytes are sent literally.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
44 The first byte within each RVTMUX packet after the opening 0x02 is the packet
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
45 type; the two packet types you will need to handle (both generate and receive)
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
46 are 0x1A for AT commands and 0x1C for TCH configuration commands.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
47
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
48 To send an AT command to the FreeCalypso GSM device, prepend the 0x1A packet
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
49 type in front of the "AT" characters, wrap the packet with 0x02 bytes on both
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
50 ends, and send it to the modem. Responses to AT commands and asynchronous
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
51 notification messages such as "RING" for incoming calls will be sent to the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
52 host as RVTMUX packets also beginning with the 0x1A packet type; they will be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
53 interspersed among other packet types, mostly debug trace output. Your system
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
54 will need to receive the RVTMUX serial byte stream continuously, parsing the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
55 packet structure and looking at the type of each packet (the first byte after
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
56 the opening 0x02) in order to detect if the modem has sent something you may be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
57 interested in.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
58
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
59 If you wish to receive a copy of all downlink TCH bits on the serial channel,
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
60 you will need to send the following 5-byte command packet to the modem:
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
61
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
62 0x02: opening flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
63 0x1C: RVTMUX packet type for TCH
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
64 0x11: TCH_CONFIG_REQ command opcode
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
65 0x01: payload byte indicating that the "forward downlink" state should be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
66 set to enabled
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
67 0x02: closing flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
68
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
69 The modem will respond with a TCH_CONFIG_CONF confirmation message (opcode
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
70 0x12), and then during all voice calls your external host will receive the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
71 following packet every 20 ms:
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
72
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
73 0x02: opening flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
74 0x1C: RVTMUX packet type for TCH
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
75 0x15: TCH_DLBITS_IND opcode
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
76 - 40 (decimal) bytes of payload -
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
77 0x02: closing flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
78
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
79 The 40 bytes of payload sent in every TCH_DLBITS_IND packet directly correspond
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
80 to the 20 16-bit words provided by the Calypso DSP in its a_dd_0 buffer. The
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
81 first 3 words (6 bytes) contains the DSP's own status information (not fully
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
82 understood by us yet, but we let you see what the DSP tells us without redacting
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
83 anything out), and the remaining 17 words (34 bytes) are supposed to contain
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
84 the TCH bits received from the GSM network in the FR codec format. Each DSP
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
85 API word is sent in the big-endian byte order, i.e., the most significant byte
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
86 followed by the least significant byte.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
87
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
88 If you wish to send your own TCH uplink bits, replacing the output of the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
89 built-in vocoder with your own alternate uplink data, you will need to send
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
90 your uplink TCH bits to the modem in packets of the following format:
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
91
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
92 0x02: opening flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
93 0x1C: RVTMUX packet type for TCH
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
94 0x13: TCH_ULBITS_REQ opcode
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
95 - 33 or 34 (decimal) bytes of payload -
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
96 0x02: closing flag
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
97
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
98 Sending 260 bits requires only 33 bytes, but the DSP operates in terms of
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
99 16-bit words, hence 17 of those words are used. The least significant byte of
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
100 the last word (i.e., the very last byte with our big-endian transmission order)
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
101 is not expected to be used, but if you send 34 bytes rather than 33, you will
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
102 have control over every bit going into the DSP API RAM in this case.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
103
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
104 There is a queue inside the firmware in which these TCH uplink data blocks are
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
105 stored; this queue is filled by the serial packet receiving handler and drained
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
106 by the L1S (synchronous) code that executes at the right times in the GSM TDMA
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
107 multiplex when uplink TCH transmission is expected. Up to 4 blocks can be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
108 queued up; as each queued-up block is transmitted on the air (more precisely,
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
109 as it is passed to the DSP for channel encoding and transmission), a
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
110 TCH_ULBITS_CONF short packet (consisting of just the opcode and nothing more)
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
111 is sent to the host. These confirmation packets can be used to pace the sending
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
112 of further TCH_ULBITS_REQs.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
113
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
114 Testing
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
115 =======
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
116
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
117 The just-described mechanism has been tested as follows:
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
118
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
119 1. I placed a call to WWV (+1-303-499-7111), and after verifying with my ear
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
120 that the downlink audio was good, I recorded the downlink TCH bits on that
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
121 call into a file with the tch record command in fc-shell.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
122
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
123 2. I placed a call to another phone (running over a live commercial GSM network)
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
124 and played the saved recording from WWV into the call uplink with the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
125 tch play command in fc-shell.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
126
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
127 3. The audio heard on the other end of the call in the previous step: the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
128 recording from WWV was definitely recognizable, but it didn't sound perfect,
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
129 i.e., it was rather garbled.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
130
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
131 [NOTE: the experiment described above was performed with an older version of
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
132 the firmware which is now codenamed Citrine, namely, the version with L1-2014.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
133 I have not played with the TCH rerouting feature again since the transition to
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
134 L1-2016.]
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
135
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
136 Further debugging of this mechanism will require two things which I currently
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
137 lack: (1) proper understanding of the workings of the GSM 06.10 FR codec and
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
138 (2) a test GSM network (as in OpenBTS/OpenBSC/etc) that could be used instead
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
139 of live commercial ones, so we could see exactly what the test MS is
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
140 transmitting on the air and what the BTS transmits in the downlink.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
141
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
142 Host side reference implementation
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
143 ==================================
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
144
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
145 If you are going to implement your own system for talking to FreeCalypso GSM
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
146 pseudo-modems via the RVTMUX binary packet interface, we strongly recommend
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
147 that you use our rvinterf and fc-shell Unix/Linux host utilities as your
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
148 starting point. You can find their source code in the freecalypso-tools Hg
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
149 repository on Bitbucket.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
150
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
151 The following test commands have been added to fc-shell for exercising the
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
152 experimental TCH rerouting mechanism:
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
153
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
154 tch record <filename>
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
155
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
156 Sends a TCH_CONFIG_REQ packet to the target, commanding the firmware to
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
157 start forwarding TCH downlink bits to the external host, and starts
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
158 recording the bits it receives in the named file. The file is written
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
159 with the same ordering of GSM 06.10 bits as used by the popular libgsm
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
160 implementation of this codec, i.e., the bits received from the GSM
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
161 device (ultimately coming from TI's DSP) are reordered before being
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
162 written into the file. It is only a reordering of bits with no change
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
163 in the information content.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
164
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
165 I was hoping that the resulting files could be played with the SoX play
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
166 command under Slackware Linux, but all I got was garbled audio, and my
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
167 audio-fu is not good enough to figure out what is wrong.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
168
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
169 tch record stop
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
170
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
171 Stops TCH downlink recording and closes the file into which the bytes
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
172 were being written; until the file is thus closed, it may not be
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
173 actually written out to the file system.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
174
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
175 tch play <filename>
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
176
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
177 Plays GSM 06.10 FR speech frames from the named file in libgsm format
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
178 (same as written by the tch record command) into the call uplink.
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
179
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
180 tch play stop
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
181
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
182 Terminates the TCH UL play-from-file operation. This command is
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
183 normally not needed, as the play session will end automatically when
cb00b90edaff documentation write-ups imported from freecalypso-sw and updated for Citrine
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
184 the end of file is reached.