PageOutline = Motorola Horizon macro BTS =

The Motorola Horizon macro BTS is a BTS model manufactured by Motorola in the late 1990ies.

It can support up to 6 TRX, typically in a configuration of 3 sectors.

There is currently no support for it in OpenBSC, but we are working on it.

Hardware

Image(horizonmacro_cabinet_door_open.jpg, 50%)
Image(horizonmacro_cabinet_top.jpg, 33%) === CTU ===

The up to 6 CTU modules are the individual transceivers (TRX) of the BTS cabinet.

They plug into the SURF RF backplane and have a front-accessible
DB9 serial port, as well as a SMA connector for the TX PA output.

This TX PA output is normally wired using a ~10cm semi-rigid SMA cable to the TX input port of a combiner/duplexer.

The CTU is of course fully shielded. But if you remove the shielding cover, it looks like this:

Image(horizonmacro_ctu_pcb.jpg, 50%)

You can see * two diversity receivers in the top left part * digital section in the top right part * transmit section (exciter) in the center * RF power amplifier in the bottom right part

==== digital part ====
The CTU digital part has the following connections * backplane connector for * power supply (27V DC) * two redundand 2048 Mbps TDM links with MCUF, manchester-encoded, 32 timeslots * three coaxial backplane connectors with SURF * Rx side A (diversity) * Rx side B (diversity) * Rx loopback (for transmitting into Rx path, loopback testing)
The CTU digital part consists of three main processors: * RSS (Radio Subsystem) * communicates with MCUF via dedicated 64kbps timeslots in TDM link * communicates via dual-ported ram with CCCP * Flash EEPROM for boot loader and 8 MByte DRAM * EQCP (Equalizer and Control Processor) * DSP for radio control and channel equalization * alarm management * downlink burst building and modulator control * tx power control * synthesizer channel control * rf frequency hopping * receiver front-end and remote tune combiner control * uplink synchronziation and equalization * diversity receiver control * automatic gain control * receiver signal sthrength calculation * CCCP (Channel Coder Control Processor) * DSP for channel coding, data routing and baseband hopping * uplink channel decoding * downlink channel encoding * A5 encryption * baseband frequency hopping * TRAU frame collection and synchronization

The CTU has a three serial consoles routed to the same DB-9 plug. We describe it in [wiki:Motorola_Horizon_macro/CTU_Console]

=== Combiner ===

The combiner / duplexer combines the TX signal of two CTU and duplexes it with the Rx path in order to be able to have two TRX attached to one antenna

=== MCUF ===

The MCUF is a full-size digital board and contains the BTS controller

Image(horizonmacro_mcuf_pcb_top.jpg, 33%)
Image(horizonmacro_mcuf_front.jpg, 33%) === NIU ===

The NIU is a E1 interface card for up to two E1 lines. Multiple NIU boards can be plugged into the rack

Image(horizonmacro_niu_pcb.jpg, 50%)

=== BPSM ===

The BPSM is a small power supply for the NIU, MCUF and other digital boards

Image(horizonmacro_bpsm_pcb.jpg, 50%)

=== ALARMS ===

The ALARMS board is monitoring FAN and other alarms in the cabinet.

Image(horizonmacro_alarms_pcb.jpg, 50%) === A-bis interface ===

The A-bis interface is via classic E1 lines. The Horizon indoor cabinet supports up to 6 E1 ports.

Each NIU module serves 1 or 2 E1 ports.

The E1 ports are physically routed to the BIB (Balanced Interface Board) module on top of the cabinet.

The pinout of the 37pin D-Sub connector on top of the BIB board has been reversed as:

	Pin		Transformer		Usage
	1		T1.1		NIUA0 Port 0 (Tx)
	2		T2.1		NIUA0 Port 0 (Rx)
	3		GND
	4		T4.1
	5		T5.1
	6		GND
	7		T7.1
	8		T8.1
	9		GND
	10		T10.1
	11		T11.1
	12		GND
	13		T13.1
	14		T14.1
	15		GND
	16		T16.1
	17		T17.1
	18		GND
	19		GND
	20		T1.8		NIUA0 Port 0 (Tx)
	21		T2.8		NIUA0 Port 0 (Rx)
	22
	23		T4.8
	24		T5.8
	25
	27		T7.8
	28		T8.8
	29		T10.8
	30		T11.8
	31
	32		T13.8
	33		T14.8
	34
	35		T16.8
	36		T17.8

Software

=== MCUF ===
There is a 20MByte Intel Series2 Flash PCMCIA card inside the MCUF. It contains software + configuration for the BTS.

Image(horizonmacro_pcmcia_iflash2.jpg, 33%)

There once has been a mtd_iflash2.c driver for Linux 2.4.x, but apparently it has never been merged mainline before the
big CardServices API redesign happened in 2.6.x. So unfortunately it's not straight-forward to read them out :(

The MCUF is able to run without the PCMCIA card. In this case, it will download all software + config via E1 from the BSC.

The MCUF has a very extensive command line interface (MMI), for more information check [wiki:Motorola_Horizon_macro/MCUF_Console] === CTU ===
It is assumed that the CTU only contains a boot loader to download the real software from the MCUF.

Further reading * Motorola BSS11 Base Station Operational Aspects (Describes BTS hardware) * http://wenku.baidu.com/view/da379c82d4d8d15abe234e32.html * Motorola SYS01 GSM SYSTEM INTERFACES (Chapter 5: Mobis) * http://read.pudn.com/downloads61/ebook/212957/SYS01.pdf