AN-30e
user manual
70-00035-01
Proprietary Redline Communications © 2004
November
16,
2004
Page 65 of 103
Figure 37: AN-30e Mobility Backhaul Deployment
Synchronization
The accuracy requirement for this reference signal varies and depends on the mobility
technology. When the reference signal is derived from the TDM network, the
interface originating this signal must be a Stratum 3 clock (see Annex B). If the
requirement is for a Stratum 1 clock, the reference signal is obtained from an external
GPS system.
Latency
The standard for mobility networks requires a return-trip-delay (RTD) of less than 25
milliseconds (BSC-to-BTS value including all devices on the link). It is not
recommended to send data traffic in a mobility network deployment, as transmitting
Ethernet data could increase the overall latency on the link. In addition, it is not
recommended to use adaptive modulation, as the modulation/coding shifts introduce
latency fluctuations and may introduce TDM synchronization errors. The Ethernet
port is always available for in-band management using SNMP, HTTP, and Telnet.
Table 22: Mobility Backhaul Operating Characteristics
AN-30e System
Performance
GSM
1
Reference
CDMA
2
Reference
Required Reference
Signal Stability
Stratum 3
Stratum 1
& Stratum 3
Stratum 1
Round-Trip-Delay (ms)
< 16
25
25
1. GSM, GPRS, UMTS
2. CDMAOne, CDMA2000 -1X, CDMA2000 1x EVDO
3. GPS source recommended for clock stability exceeding Stratum 3.
Table 23: AN-30e Operating Settings -- Mobility Backhaul
Ethernet Port
10BaseT, Full Duplex
1
Jitter Buffer (ms)
8
Packet Length (bytes)
E1 Unframed (framed): 256 (248)
T1 Unframed (framed): 200 (192)
1. Management traffic only (i.e., HTTP Web interface).
6.1.4 Enterprise
Networks
Traditional TDM is used as a last mile transport for data, voice, and video traffic to
Enterprises and private networks. The following figure illustrates a typical Frame
Relay deployment using the AN-30e wireless system.
Synchronization
TDM devices operate in a master-slave relationship and use a reference clock derived
from the TDM signal. The clock accuracy requirement on a TDM network is
dependent on the distance from the equipment to the core. A typical requirement for
enterprises and private networks is Stratum 4 clock.
