Technology

VectaStar’s advanced technical features make it the ideal solution for Cellular backhaul, WiMAX backhaul, and Enterprise Access, or a network that combines more than one of these applications.

The most cost-effective solution for backhaul

Three primary technology features: E1 optimisation, a very efficient MAC, and inherent very low latency allow VectaStar to support statistical multiplexing. Combined with very high capacity, these primary technology features make VectaStar the most cost-effective solution for backhaul.

E1 optimisation

VectaStar supports transparent optimisation techniques of both Abis and Iub interfaces to make better use of the available backhaul bandwidth.

While optimisation is not unique, VectaStar is the first and only point-to-multipoint wireless platform that provides Abis optimisation. Implementation is either on or off, with no user configuration necessary. All optimisation is performed dynamically ‘on-the-fly’, and with complete transparency resulting in more efficient use of the Abis interface, reduced bandwidth, and overall increased effective backhaul network capacity.

VectaStar Abis optimisation

The Abis interface transports signalling protocols and compressed voice data between the BTS and BSC in a GSM network. To further reduce number of leased lines required between the BSC and MSC, VectaStar supports transparent Abis optimisation. In a live network, VectaStar has consistently reduced the bandwidth requirement by as much as 80%.

Bandwidth reduction through Abis optimisation

VectaStar Iub optimisation

The Iub interface transports signalling protocols and compressed voice and data between the Node B and the RNC in a UMTS network. To further reduce the bandwidth required in leased lines between the RNC and UMSC, VectaStar supports transparent optimisation of the Iub interface.

• IMA E1 interfaces converted to AAL5/AAL2 with idle cells removed
• VPI/VCI mapped to Virtual Channels
• AAL5 and AAL2 handled on different Virtual Channels
• Statistical multiplexing of both AAL5 and AAL2 ‘on air’

Real-world examples of VectaStar optimisation in a live network

A South East Asian network operator is using VectaStar to backhaul traffic from multiple 2G and 3G cellular base stations. A monitor of network traffic as VectaStar E1 optimisation takes affect shows the greatly reduced bandwidth requirements.

• (A) Optimisation switched on for the first E1
• (B) Optimisation switched on for the second and third E1
• (C) Optimisation switched on for the fourth Iub E1

Low latency

VectaStar round trip latency

Radio network latency is defined as the additional time a message takes to transfer between two devices while passing through the radio network compared to a wire connection. For real-time applications a low latency network is an advantage. Typically, latency is measured from a source to a destination and back again – the ‘round trip’ time. VectaStar has a very low latency of less than 2ms round trip.

Efficient MAC

VectaStar is currently the most spectrally efficient fixed wireless access platform available making it ideal for both backhaul and access networks.

There are two favoured methods of using the spectrum to transmit data

• Time Division Duplex (TDD)
• Frequency Division Duplex (FDD)

TDD is favoured by unlicensed radio products; for example, UNII band in the USA. FDD is favoured by licensed bands; for example, 3.5GHz in Europe.

In an FDD such as VectaStar, two radio channels are allocated typically separated by 100MHz. All transmission occurs in one channel whilst all reception occurs in the other channel.

IP throughput

The gross and (net) data rates are for all operating frequencies (3.5GHz, 10.5GHz, and 26GHz) and show Ethernet services for a single Access Point.

Channel	QPSK	16QAM	64QAM
1.75MHz	2.5 (2.0) Mbps	5.0 (3.9) Mbps	7.5 (5.6) Mbps
2.5MHz	4.0 (3.2) Mbps	8.0 (6.2) Mbps	12.0 (9.0) Mbps
3.5MHz	5.7 (4.6) Mbps	11.4 (8.9) Mbps	17.1 (12.8) Mbps
5MHz	8.0 (6.4) Mbps	16.0 (12.5) Mbps	24.0 (18.0) Mbps
7MHz	11.4 (9.1) Mbps	22.9 (17.8) Mbps	34.3 (25.7) Mbps
10MHz	16.0 (12.8) Mbps	32.0 (25.0) Mbps	48.0 (36.0) Mbps
14MHz	20.0 (16) Mbps	40.0 (31.2) Mbps	60.0 (45.0) Mbps

E1 throughput

E1 throughput before optimisation.

Channel	QPSK	16QAM	64QAM
1.75MHz	1.0	1.9	2.7
2.5MHz	1.6	3.1	4.3
3.5MHz	2.3	4.4	6.1
5MHz	3.2	6.1	8.6
7MHz	4.5	8.7	12.3
10MHz	6.3	12.2	17.2
14MHz	7.9	15.3	21.5

Statistical multiplexing

Statistical multiplexing enables operators to monitor and analyse network traffic, and allocate capacity accordingly. VectaStar enables network operators to perform statistical multiplexing to achieve optimum network performance, increase the effective backhaul capacity, and avoid costly network upgrades.

Statistical multiplexing enables a reduction in the effective bandwidth required to carry traffic from multiple BTS sites. Statistical multiplexing advocates the advantage that the load characteristics of each BTS are different over time.

Statistical multiplexing for five BTS sites

Real-world examples of VectaStar statistical multiplexing in a live network

A South East Asian network operator is using VectaStar to backhaul traffic from multiple 2G and 3G cellular base stations. The E1 traffic during one week period peaks at 14Mbps.

Traffic peaks for five BTS sites over seven days

Using VectaStar statistical multiplexing allows traffic from a group of BTSs to be packed more efficiently reducing the bandwidth needed to carry the traffic in the transport network. VectaStar is unique in offering statistical multiplexing and is only possible from a point-to-multipoint system. Using VectaStar the operator is able to pack traffic from the five BTS sites more efficiently, and overall peak demand reduces from 14Mbps to 3.1Mbps.

Statistically multiplexed traffic peaks at just 3.1Mbps

High capacity

Capacity defines the amount of information a network can transport.

VectaStar capacity scales to meet the network demands

Flexible, scalable future-proof platform

Multi-frequency operation, industry-standard interfaces, and support for varied protocols make VectaStar a multiple service platform for cellular backhaul, WiMAX backhaul, Enterprise access or a combination of all three.

Multi-frequency operation

VectaStar is currently available in three operating frequency bands that have different operating characteristics. Operators can choose different frequency equipment to suit particular deployment situations. As VectaStar is a modular system, a single set of base station equipment will support any combination of Access Points irrespective of their operating frequency.

VectaStar multi-frequency platform

Characteristics of operating frequencies

3.5GHz operation

Excellent coverage with good non line-of-sight capability

Unaffected by rain fade

Smaller frequency allocation than higher frequency bands

10.5GHz operation

Ideal for short range line-of-sight installations

Affected by rain fade

Good frequency allocation in most countries

26GHz (24.5–26.5GHz) operation

Line-of-sight operation making installation and planning simple

Greatly affected by rain fade necessitating careful planning and deployment

Generous frequency allocations world-wide

Line-of-sight (LOS) and non line-of-sight operation (NLOS)

Any radio link where there is partial obstruction between the transmitter and receiver will suffer a degradation in performance owing to excess path loss (path loss in excess of free space loss). Line-of-sight (LOS) coverage and in particular non line-of-sight (non-LOS) coverage is determined by the link budget. A generous link budget allows a radio system to tolerate high path loss.

VectaStar has many features that enable excellent performance at all frequencies in line-of-sight deployments and exceptional non line-of-sight operation at 3.5GHz allowing an operator to trade link budget against capacity and cost.

• Three power amplifier options
• 25dBm low power amplifier
• 29dBm medium power amplifier
• 33.5dBm high power amplifier (3.5GHz model)

• Adaptive modulation
• QPSK, 16QAM and 64QAM modulation schemes
• QPSK modulation for increased range
• 64QAM modulation for increased throughput

• 10 channel sizes from 1.75MHz to 14MHz
• 1.75MHz channel for increased range
• 14MHz channel for increased capacity

• Circular polarised antennas (3.5GHz model)
• Reduce multipath for improved non-LOS performance
• Reduce reflections for higher CNR in frequency re-use patterns

• Adaptive equalisation
• 128 symbol sequence radio channel
• Decision Feedback Equaliser reduces delay spread through reflections from nearfield objects
• Delay spread tolerance: 3.6μs in a 14MHz channel rising to 28.8μs in a 1.75MHz channel.

Industry-standard interfaces

VectaStar is based around an ATM core and employs a highly efficient Medium Access Controller that enables the delivery of a diverse range of services – a truly flexible platform!

Varied protocol support

VectaStar supports varied protocols both directly and indirectly through third-party interface units.

• Multiple E1/T1
• Ethernet IP
• 802.1q VLAN
• Abis
• Iub
• ATM

Multiple services

Each service is carried over a proprietary ATM VC that can be configured for

• Independent uplink and downlink modulation: QPSK, 16QAM or 64QAM
• Bandwidth: peak rate limit (PIR) and committed rate limit (CBR)
• Scheduler Priority
• CBR or non CBR service
• CBR synchronisation clock scheme
• Ethernet and IP QoS

Service	AAL	Priority	PIR	CBR	Eth QoS	IP QoS
3G backhaul	AAL2, 5	medium	varies	varies	–	–
WiMAX backhaul	AAL5	high	CBR	CBR	yes	yes
2G backhaul	AAL1	high	CBR	CBR	–	–
E1	AAL1	high	CBR	CBR	–	–
T1	AAL1	high	CBR	CBR	–	–
WiFi backhaul	AAL5	high	CBR	CBR	yes	yes
Circuit service	AAL1	high	CBR	CBR	–	–
VoIP	AAL5	high	VBR	VBR	yes	yes
CCTV	AAL5	low	varies	varies	yes	possible
VLAN	AAL5	medium	varies	varies	yes	–
Internet	AAL5	low	varies	varies	–	possible
DSLAM	AAL5	medium	varies	varies	yes	possible
VPN	AAL5	medium	varies	varies	yes	possible
Email	AAL5	low	UBR	UBR	–	–
FTP	AAL5	medium	varies	varies	–	–