VectaStar Gigabit System OVERVIEW VectaStar System Overview VectaStar Gigabit is a highly flexible Carrier Class Point-to-Multipoint (PMP) transmission platform operating at 10.5GHz, 26GHz, and 28GHz and offering a compelling alternative to Point to Point (PtP) radio and leased lines. VectaStar Gigabit PMP systems deliver significant Capex and Opex advantages over PtP. With PMP, radio and antenna hardware quantities are approximately halved as are installation costs. Tower loading and rental are dramatically reduced. Savings can also be made on licence fees because PtP uses a dedicated frequency pair license per connected site whereas PMP uses just one frequency pair per sector, to connect up to 30 sites. VectaStar is the most widely deployed and technically advanced PMP platform and is used around the world to backhaul 2G, 3G, HSPA, WiMAX and LTE networks, as well as to provide carrier-grade corporate access. VectaStar provides backhaul options for Mobile Network operators and access for Broadband and Enterprise operators VectaStar Gigabit can backhaul up to 64 separate Ethernet and TDM (E1 and ATM) based services per link, and it can support TDM and Ethernet based synchronisation schemes used in a variety of different network types.
VectaStar Gigabit is therefore ideally suited to backhaul multiple RAN technologies from common base station sites. VectaStar Gigabit can consolidate the traffic from these networks, support the different synchronisation requirements, and backhaul them effectively. This provides mobile network operators an easy migration of their backhaul from legacy networks going forward onto newer network implementations such as LTE. VectaStar Gigabit (VSG) deployments can vary from single sector outdoor only installations to fully redundant multi-sector radio hubs. System Components Access Point (AP): The VectaStar Gigabit Access Point (AP) is an alloutdoor integrated radio, modem and network interface unit, connecting directly to a sector antenna. An AP can operate a single sector without any additional indoor equipment (Zero-footprint mode), backhauling Ethernet traffic from up to 8 remote terminals and terminating it on a single GigE interface. Up to 30 remote terminals per AP can be supported with the addition of the Radio Controller. The AP may be connected and powered either over a single CAT-5e cable or by 2-core cable for power and a single mode fibre for data. AP & Sector Antenna Remote Terminal (RT): The VectaStar Gigabit Remote Terminal (RT) is an all-outdoor integrated radio, modem and network interface unit, connecting directly to a parabolic antenna. RTs offer class-leading full duplex throughput up to the available sector capacity of 175Mbps gross (150Mbps net Ethernet) in each direction (at 256QAM in a 28MHz channel). Power and data are provided over a single CAT-5e cable. Alignment of the RT to the AP is performed using the dedicated alignment interface (BNC) and a standard voltmeter. RT & 30cm Antenna Antennas: AP and RT outdoor units have a slip-fit waveguide interface which permits direct mounting to the rear of sector horn and parabolic antennas respectively. The slip-fit design permits the use of the same AP outdoor unit on either vertically or horizontally polarised sector horn antennas. Sector antennas with typically 90 degrees beam-width are supported. All outdoor units may be replaced without disturbing the antenna alignment. Radio Controller: The VSG Radio Controller (RC) is a flexible, high capacity switch which aggregates traffic from multiple APs onto Gigabit Ethernet or 10 Gigabit Ethernet* interfaces. All traffic interfaces are SFP-based providing maximum interface flexibility. The RC s high capacity backplane supports up to 10 Gbps sustained operation between any set of GE and 10GE* ports. Up to 8 AP sectors can be controlled by a single RC and while a VSG AP on its own supports up to 8 RTs per sector, use of the RC increases this capacity up to 30 RTs per sector. The RC incorporates programmable high speed logic allowing software upgradability for future performance enhancements and support of new network standards. The RC is easily managed by means of two RJ45 10/100BASE-T ports or a DB9 serial port. In-band management on the GE or 10GE* core network connections is also supported. For networks requiring the highest availability, a number of protection features exist, such as 1:1 port redundancy where ports can be spread across a pair of RC devices when RC redundancy is configured. If only
outdoor unit (AP) redundancy is required, then a single RC can support up to 4 1+1 redundant pairs of APs or up to 4 2+0 redundant sectors. Where redundant RCs are used to provide indoor redundancy, up to 4 non redundant APs can be supported on each RC. Alternatively indoor and outdoor redundancy is possible with 2 RCs supporting either up to 6 1+1 redundant sectors or up to 4 2+0 redundant sectors. Remote Terminal Indoor Units (IDU): The RT outdoor unit is data connected and powered over Cat-5e cable which is terminated by either a Gigabit Power Injector (GPI) for Ethernet only services, or via a 1U 19 rack mountable indoor unit (IDU-4E1-4VL). The Gigabit Power injector accepts -48V DC power supply, and a single GigE interface. Where up to 4 Fast Ethernet interfaces (100BaseT) are required, and/or up to 4E1s, then the IDU-4E1-4VL is required. TDM E1 services: Support for TDM services (E1, ATM) is optionally available by the addition of a 1U Multi- Protocol Aggregator and or a 1U E1 Concentrator. At a multi-sector radio hub, up to 126 E1 s can be terminated to the core over channelized STM-1 per co-located Multi Protocol Aggregator (MPA). E1 Concentrators co-located with the RC can each provide up to 8 E1 network terminations for E1s from RT sites. Additionally, E1 Concentrators may be used to collect up to 8 E1s per concentrator from equipment located at the radio hub and pass these via the RC to channelized STM-1 core connections of the MPA(s). System Capabilities System capacity: Using a 28MHz channel with 256QAM, an AP can deliver a peak of 150Mbps net Ethernet throughput, full duplex, shared between the RTs in the sector. Given that the mobile data traffic load is highly variable (high Peak to Average ratio), and largely de-correlated per base site (RT), the sector traffic is composed of the sum of the average traffic loads, rather than the sum of the peaks (as would be the case in combining several PtP links). VSG PMP systems take advantage of this traffic distribution and employ statistical multiplexing which can multiply the sector capacity of 150Mbps by a factor of approximately 2. A comparison between PtP and PMP of backhauling traffic from 14 sites from an actual HSPA+ network is shown below:
In the case of PtP it is necessary to provision 14 licenced links for a cumulative peak bandwidth of at least 160 Mbps. This could be achieved with 14 links each operating typically 7 MHz channels. It can be seen that in the case of VSG PMP the same network traffic can be backhauled in one 150 Mbps sector with a single 28MHz channel with traffic peaking at approximately 95 Mbps giving a PMP statistical multiplexing gain of 1.68x (160 Mbps / 95 Mbps). The spectrum required for PtP is 98 MHz compared with just 28 MHz for PMP giving PMP a saving of 75% on spectrum utilisation. Furthermore, the PMP solution is able to release the additional headroom ( white space in the diagram) created by the increased efficiency to any site in the sector on demand thereby delivering superior customer experience when the customer or site requires additional resources. Robust Links: VSG ensures robust link integrity by using a number of techniques including Automatic Transmit Power Control on the RTs, Automatic Gain Control on the receivers of both APs & RTs and Adaptive Modulation. The Adaptive Modulation can vary in 7 steps between 256QAM with Trellis coding down to QPSK, and is hitless i.e. it occurs fast enough for error correction to mask any on-air errors (e.g. changes down within a few ms of a fade occurring). The change to a higher modulation is also hitless but takes place on a longer timescale, to ensure stability and prevent rapid oscillations between modulation states. The modulation is determined per service, and can be set as Adaptive, Static, or Adaptive but Capped. This means that the link margin to determine robustness to changing atmospheric conditions can be set per service, not just per link. Traffic Prioritisation: VSG can prioritise every service within a sector according to a set priority level, or dynamically using the 802.1P priority code point (PCP) field. There are 4 priority levels, the highest of which is reserved for TDM services, and the remaining 3 for Ethernet services. Capacity is allocated across the sector according to priority level, so that the most important services are assured adequate capacity, and that any link degradation due to atmospheric conditions only impacts the lower priority traffic. This is true across the sector, so the sector scheduler will ensure higher priority traffic on impaired links will be granted additional capacity at the expense of low priority traffic on an unaffected link. In addition, capacity per service can be managed by setting Peak Information Rate (PIR - limiting per service,
occurring at the input to each queue) and Committed Information Rate (CIR). If CIR values are set, then the round robin scheduler is weighted such that services which are sending data below their CIR setting are scheduled ahead of those which have sent data, on average, above their CIR setting. This is applied within the priority class so higher priority services can stop lower priority services from achieving their CIR. Multiple synchronisation mechanisms supported: VSG systems support IEEE 1588V2 and NTPv4 synchronisation schemes. An external clock input option is available on the RC. VSG is capable of backhauling multiple services on mixed technology Radio Access Networks. As an example, at a co-located BTS/NodeB site, VSG can simultaneously support a legacy GSM BTS connected via E1s with synchronisation over an E1 clock, and an HSPA NodeB connected via Ethernet with synchronisation determined by a packet timing mechanism such as 1588v2, NTP or a similar derivative. VSG hardware is SyncE* ready to support networks such as LTE. Latency: VSG uses a proprietary scheduling mechanism to ensure a superior latency performance compatible with LTE network requirements. This delivers an average IP latency of less than 0.6ms with 99.9% < 1.0ms (at <=98% rated sector throughput). Links to the core network: Where the Radio Controller is used at the radio hub, it can provide flexible connections to the core network. For Ethernet, the RC can use 2 SFP interfaces for redundant GE core network Interconnect. Two SFP+ 10 Gigabit Ethernet (10GE)* ports are also provided for future use for core network interconnection to accommodate total aggregate rates from a full set of sectors exceeding 1 Gbps. The RC can be equipped with STM-1 SFP s to manage and control other VectaStar hub equipment namely the Multiple Protocol Aggregator (MPA - to support STM-1 channelised VC-12 and un-channelised VC4) and the 8 E1 Concentrator to support co-located services and raw E1 from the network. Resilience of operation: The VSG RC can provide redundancy of operation in a number of different ways. Many operators face restrictions on when they can carry out mast top work, and so time to fix is a critical issue. VSG can provide resilient sectors by managing redundant APs, in both a hot standby 1+1 configuration, and also in a dual operation 2+0 using 2 channels. This latter configuration doubles the sector capacity in normal operation.
Where operators are primarily concerned with resilience of operation for high traffic concentrations, VSG can offer full switch redundancy by using a dual RC configuration, and if appropriate the Multi-Protocol Aggregator (MPA). The RC(s) and MPA(s) can also provide redundant connections to the core. Migration of VectaStar2 systems to VectaStar Gigabit systems: The RC can control and operate systems with Gigabit Ethernet APs, or with older VectaStar2 APs or with a mix of the two types. The RC also supports a mix of VSG RTs and VectaStar2 CPEs in the same sector; this is true for VSG APs and VectaStar 2 APs. The RC therefore offers a way for operators to migrate VectaStar2 systems forward into VSG, thereby providing a route to enhancing the capacity and capabilities of their backhaul network. Network Management System (VNMS) VectaStar Network Management System (VNMS) provides a graphical user interface for network operators to configure, manage and monitor their VectaStar network. Using carrier-class server hardware and operating system software, VNMS provides a cost effective, highly reliable and scalable server and client platform. VNMS web-based graphical user interface supports multiple simultaneous users located either remotely or locally from the Network Operations Centre. VNMS provides core FCAPS functionality, in accordance with ITU-T standards to provide a standalone network management solution for VectaStar networks. In addition using SNMP, XML or CSV files, the VNMS northbound interface can also be integrated with third party OSS systems such as Netcool, TeMIP etc. * Roadmap Item To confirm the latest product information and availability, and to find your nearest Cambridge Broadband Networks representative, please contact our head office on sales@cbnl.com or visit http://www.cbnl.com HEAD OFFICE Cambridge Broadband Networks Limited, Selwyn House, Cowley Road, Cambridge, CB4 0WZ, UK T +44 1223 703000 F +44 1223 703001 SOUTH AFRICAN OFFICE Cambridge Broadband Networks Limited, Constantia View Office Estate Block 4, Ground Floor, 2 Hogsback Road, Quellerina Ext 4, Roodepoort, 1709, South Africa T +27 11 581 1500 F +27 11 581 1520 NIGERIAN OFFICE Cambridge Broadband Networks Limited 11 Awolowo Road Ikoyi, Lagos Nigeria Version A022 Copyright 2011. Cambridge Broadband Networks Limited. Cambridge Broadband Networks Limited reserves the right to make changes to the specifications of the products detailed in this document at any time without notice and obligation to notify any person of such changes. VectaStar is a registered trademark. All other trademarks are acknowledged and observed. Mention of third-party products does not constitute an endorsement or a recommendation.