First I’d like to show you the network architecture that I filched from www.ccpu.com:

On the network architecture above, we can see 4G(3G LTE/SAE), 3G/3.5G HSPA, and IMS convergence. It should be noted that the picture above implement backward compatibility technology i.e., 3GPP IMT 2000 and IMT advanced.

We know, beside 3GPP there’s another technology such as 3GPP2 (based on CDMA2000 evolution and UMB) and also WiMAX. So… how we choose the interoperability scenario for this various technology?

Below I give another picture from www.telkom.info, so we can distinguish the differences

hmm… is there any left behind? yup, we haven’t talked about WiMAX Network architecture yet. So below I post another picture related to WiMAX architecture:

Well, after we know each network architecture, now we will begin to discuss about the interoperability or interworking between them.

First of all, we have to equalize our perception about network architecture. Commonly, we can divide the network architecture into three main parts, i.e., Radio Access Network, Transmission Network ( Transport) and Core Network.

Well, after we have same perception about network architecture, now we can focus on Radio Access Network which is experienced rapid development in this 5 past years.

Hmm… as mentioned on Wikipedia, 4G objectives are:

• A spectrally efficient system (in bits/s/Hz and bits/s/Hz/site)
• High network capacity: more simultaneous users per cell,
• A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions as defined by the ITU-R,
• A data rate of at least 100 Mbit/s between any two points in the world,

for the points above, let’s take a look this picture:

what can we see on the picture above is: all the evolution are using OFDMA!! so we can conclude that 4G technology are seems to be OFDMA and it’s evolution using MIMO, MISO, beamforming, etc. in order to achieves high network efficiency, high network capactiy, high data rate ( though less than 100 Mbps ). In other word: LTE, UMB, and WiMAX just like a brother and sister huh..

• Smooth handoff across heterogeneous networks,
• Seamless connectivity and global roaming across multiple networks,

for this two point above, I have my own opinion: All the network which is standardized by 3GPP and 3GPP2 are based on wide area concept ( GSM, CDMA, 3G UMTS, LTE, UMB). So how about the other network such as PAN, WLAN, which is based on small area concept?? How we can make those network interwork each other? As we know that on 4G beside horizontal handover ( intrasystem handover ), 4G system should have vertical handover capability ( intersystem handover ) to get the network access in harmony with user application QOS. So… we have to build a hybrid network which can adopt wide area concept and small area concept in to one system. The alternative solution is to have Software Defined Radio on the User Equipment. With this kind of technology, smooth handover across heterogeneous system and global roaming across multiple networks can be achieved :D.

• High quality of service for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc)
• Interoperability with existing wireless standards, and
• An all IP, packet switched network.

hmm.. now we are going to discuss about the three last points. Well, as we have discussed above the most rapidly development technology is on the Radio Access side. But don’t forget, on 4G we have to maintain QOS for various application, over IP end to end network, without ignoring the interoperability with the existing wireless standards. So… what should we do??

Thanks god.. we have IMS. Yup!! the IP Multimedia Subsystem. With this element on the core network, what ever the radio access technology as long as it use IP, IMS can handle it. And don’t forget IPv6 to address all of equipment in this world…hehehe…

btw…jd inget slogan makanan : “Apapun makanannya, minumnya teh Botol Sosr*!!”, mungkin dalam dunia telekomunikasi… bisa kita ubah slogan tersebut menjadi: “Apapun teknologi akses radionya…core networknya: IMS!! ”

Well… maybe sometimes I’ll make an article about IMS… (after I’ve learned about it…). Thanks for the attention…hope this article will be useful. I’m sorry if there’s a lot of mistakes.. and I well opened to discuss it