Network Architecture Evolution - 1G to 4G

As we can see in the above diagram, aprt from transport technology migration from TDM to "All-IP"  LTE/4G architecture retains many similarity to 1G - AMPS Network. 

The major difference is that the Central Core (i.e. MTSO) in AMPS was handling both User and Control Planes. But in 4G they are separated to allow independent growth and modernization along with extensive reduction in "LATENCY".

LATENCY was not at all a factor during 1G or Initial 2G Periods. 

Since LTE is more of a "DATA" network and supports Voice in the form of VoIP, it provides the flexibility in using the Voice CODECS  depending upon various factors. But 2G Networks are still having a fixed rate/codec (sets) due to their radio access technology.

Eventhough GSM networks are suffering the lack of flexibility like LTE/LTE-A/3G networks, there are some steps taken by major vendors to revive this market based on the interest from existing 2G Only operators/ the ones who has a license in hand.

There are many hurdles in the form of existing 2G operator to become a LTE Operator. May be a regulatory/license obligation/business viability can halt them.

From my opinion, Voice is still going to rule for a while in the form of 2G Networks.The proof, Single Radio Voice Call Continuity (SRVCC) /VoLTE are developed not only to provide a smooth migration, also will help 4G Operators to offload all their Voice Service demand from their customers to 2G Networks.

So Technology oriented licensing which cornered the 2G Operators hsa a greater chance in reviving their business in the form tie ups with 4G Operators.

Reference :Telefónica makes first multivendor VoLTE-to-3G call handover

Reference : US Wireless Carriers Move to New Technology—for Voice

 

 

High Speed Links (HSL) & ATM Bundling

Since HSL is using ATM Bundling technology, they create one tunnel containing 30 time slots to achieve the 2 Mbps link speed. (30 * 64 = 1920) is the actual available bandwidth for the signaling traffic.

Nowadays both NSN & HUAWEI support the bundling of 8 time slots to one HSL Link. So that they can use the remaining time slots for some other purpose/links. For an example in Huawei they can map some of the incoming signaling link to another PCM without even doing any MTP3 level analysis.

Even though number of SIGTRAN deployments are growing fast, but still HSL will exist for a while till the IP-fication completes everywhere.

The traditional Narrow-band / LSL C7 Link Set capacity was 16 Links * 64 Kbps = 1024 Kbps.Where using HSL technology we can achieve a capacity of 16 Links * 1920 Kbps = 30 Mbps capacity.