Wireless Communication Technologies: that connect the entire world without limit.

Md. Bahadur Ali

GM (Finance & Accounts)

Network technology plays a significant role in the science and business area. Scientists innovate and develop some new technologies to fit businesses’ needs and to satisfy people’s demands. The first generation, 1G wireless mobile communication systems, was introduced in the early 1980s and completed in the early 1990s. 1G wireless was analog and supported the first generation of analog cell phones with the speeds up to 2.4kbps. The second generation, 2G system, fielded in the late 1980s and finished in the late 1990s, was planned mainly for voice transmission with digital signal and the speeds up to 64kbps. The third generation, 3G wireless system, was developed in the late 1990s and might be well-done in the late 2000s. 3G is not only provided the transmission speeds from 125kbps to 2Mbps, but also included many services, such as global roaming, superior voice quality and data always add-on. The fourth generation (4G) is a conceptual framework and a discussion point to address future needs of a high seed wireless network that can transmit multimedia and data to and interface with wire-line backbone network perfectly just raised in 2002. The speeds of 4G can theoretically be promised up to 1Gbps. The beyond will be 5G with incredible transmission speed with no limitation for access and zone size.

The main distinguishing factors between 3G and 4G will be data rates, services, transmission ways, access technology to the internet, the compatibility to interface with wire-line backbone network, quality of service and security. 4G should support at least 100 Mbps peak rates in full-mobility wide area coverage and 1Gbps in low-mobility local area coverage. The speeds of 3G can be up to 2Mbps, which is much slower than the speeds of 4G. For the service, 3G marketing is difficult to roam globally and interoperate across networks, yet 4G will be a global standard that provides global mobility and service portability so that service provider will not longer be limited by single-system. In order words, 4G should be able to provided very smooth global roaming ubiquitously with lower cost. Furthermore, 3G is based on a wide-area concept applying circuit and packet switching for transmission with limited access technology, such as WCDMA, CDMA and TD-SDMA. However, the 4G standard will base on broadband IP-based packet switching method of transmission with seamlessly access convergence. It means that 4G integrated all access technologies, services and applications can unlimitedly be run through wireless backbone over wire-line backbone using IP address. In the other words, 4G will bring us almost perfect real world wireless or called “wwww: World Wide Wireless Web.

Comparison among technologies (Generations)

Generation	Definition	Throughput/ Speed	Technology	Time period	Features
1G	Analog	14.4Kbps (peak)	AMPS, NMT, TACS	1970-1980	During 1G Wireless phones are used for voice only
2G	Digital Narrow band circuit data	9.6/14.4 Kbps	TDMA, CDMA	1990-2000	2G capabilities are achieved by allowing multiple users on a single channel via multiplexing. During 2G Cellular phones are used for data also along with voice.
2.5G	Packet Data	171.2 Kbps (peak) 20-40 Kbps	GPRS	2001-2004	In 2.5G the internet becomes popular and data becomes more relevant. 2.5G multimedia services and streaming starts to show growth.
3G	Digital Broadband Packet Data	3.1 Mbps (peak) 500-700 Kbps	CDMA 2000 (1xRTT, EVDO) UMTS, EDGE	2004-2005	3G has Multimedia services support along with streaming are more popular. In 3G, Universal access and portability across different device types are made possible. (Telephones, PDA,s, etc.
3.5G	Packet Data	14.4 Mbps (peak) 1-3 Mbps	HSPA	2006-2010	3.5G supports higher throughput and speeds to support higher data needs of the consumers.
4G	Digital Broadband Packet All IP Very high throughput	100-300 Mbps (peak) 3-5 Mbps 100 Mbps (Wi-Fi)	WiMax LTE Wi-Fi	Now (Read more on Transitioning to 4G)	Speeds for 4G are further increased to keep up with data access demand used by various services. High definition streaming is now supported in 4G.
5G	Not Yet	Probably gigabits	Not Yet	Soon (probably 2020)	Currently there is no 5G technology deployed. When this becomes available it will provide very high speeds to the consumers.

How 4G works:

In the 4G wireless networks, each node will be assigned a 4G-IP address (based on IPv6), which will be formed by a permanent “home IP address and a dynamic” care-of address that represents its actual location. When a device (computer) in the Internet wants to communicate with another device (cell phone) in the wireless network, the computer will send a packet to the 4G-IP address of the cell phone targeting on its home address. Then a directory server on the cell phone’s home network will forward this packet to the cell phone’s care-of address through a tunnel, mobile IP; moreover, the directory server will also inform the computer that the cell phone’s care-of address (real location), so next packets can be sent to the cell phone directly. The idea is that the 4G-IP address (IPv6) can carry more information than the IP address (IPv4) that we use right now. IPv6 means Internet Protocol Version 6 including 128 bits, which is 4 times more than 32bits IP address in IPv4. 32 bits IP address looks like this 216.37.129.9 or 11011000.00100101.10000001.00001001 (32bits). However, the IP address in IPv6 version will be 4 times of IPv4; it looks like 216.37.129.9, 79.23.178.229, 65.198.2.10, 192.168.5.120. It includes 4 sets of IPv4 address defined in different functions and usages. In previous example for the case, the first set of the IP address (216.37.129.9) cab be defined to be the “home address purpose. It just likes the normal IP address that we use for addressing in the Internet and network. The second set of the IP address (79.23.178.229) can be declared as the “care-of address. It is the address set up for the communication from cell phones to computers. After these addresses from cell and PC established a link, care-of address will instead of home address; it means that communication channel will switch from the first set to the set to the second set of the IPv6 address. The third set of the IP address (65.198.2.10) can be signed as a tunnel (mobile IP address). It is the communication channel to wire-line network and wireless network. An agent, a directory server, between the cell phones and PC will use this mobile IP address to establish a channel to cell phones. Then, the last set of IP address (192.168.5.120) can be local network address for virtual private network (VPN) sharing purpose. In this rich data IP address, software can use them to distinguish different services and to communicate and combine with other network areas, such as computer (PC) and cell phones network in the case of the example. In addition, the table bellow is a basic comparison of IPv6 and IPv4 showing that how IPv6 richer than IPv4 in data containing capacity. Moreover, in 4G wireless network, not only has it IPv6 transmission protocol, but also be supported by OFDM, MC-CDMA, LAS-CDMA, UWB and Network-LMDS.

OFDM stands for Orthogonal Frequency Division Multiplexing, transmitting large amounts of digital data over a radio wave. OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver. In the other words, OFDM is a digital modulation technology in which in one time symbol waveform, more than thousands of orthogonal waves are multiplexed for increasing signal strength. This is good for high bandwidth digital data transition. In OFDM, two wireless devices will establish a connection tunnel before they start their communication. Therefore, after making a connection between a certain target, the radio signal will split into many smaller sub-signals with accurate direction to the target.

MS-CDMA stands for Multi-Carrier Code Division Multiple Access, which is actually OFDM with a CDMA overlay. The users are multiplexed with orthogonal codes to distinguish users in MS-CDMA and single-carrier CDMA systems. It allows flexible system design between cellular system and signal cell system. However, in MC-CDMA, each user can be allocated several codes, where the data is spread in time or frequency.

LAS-CDMA, Large Area Synchronized Code Division Multiple Access, is developed by LinkAir Communication, a patented 4G wireless technology. “Las-CDMA enables high-speed data and increases voice capacity and the latest innovative solution, Code-Division Duplex (CDD), merges the highly spectral efficient LAS-CDMA technology with the superior data transmission characteristics of Time-Division Duplex (TDD) This resulting combination makes CDD to be the most spectrally efficient, high-capacity duplex system available today. In the 4G area, LAS-CDMA is played as a global transmission protocol (“World Cell) as showing in the following picture, Zone size. It means that if the distance is too for to two wireless devices, they have to use this protocol with IPv6 to establish their connection.

In 4G technologies, UWB radio can help solve the multi-path fading issues by using very short electrical pulses to across all frequencies at once. However, UWB can only be used indoor or underground because of its low-power requirement. Thus, UWB has to be used with OFDM, which can transmit large among of digital data with multi-path algorithm; OFDM running outdoor, UWB running indoor to ensure signal strength purpose. In the 4G wireless technology, UWB will be played as “Pico Cell of very limited distance in the buildings.”

The Network-LMDS, Local Multipoint distribution system, is the broadband wireless technology used to carry voice, data Internet and video services in 25GHz and higher spectrum. Its broadcast method consisted simultaneous voice, data, Internet, and video traffic can be the solution of signal fading issue in local area. Therefore, Network-LMDS can be played as Micro Cell and Micro Cell in the 4G technology to be the main transmission protocol for the wireless devices, showing as the picture below.

The idea of the complementation of IPv6, OFDM, MC-CDMA, LAS-CDMA, UWB and Network-LMDS can be arranged in different zone size. IPv6 can be designed for running in the all area because it is basic protocol for address issue LAS-CDMA can be designed for the global area as zone 1, world cell. OFDM and MC-CDMA can be designed for running in the wide area (zone 3), called Macro cell. Network-LMDS in Zone 2, Micro cell and UWB is in Zone 1, Pico cell. Based on above transmission protocol, we knew that each of them has its drawback(s) in somewhere; although the complementation with all of them, it is not perfect yet go implement 4G’s great idea. Academic research and experiments are still required for further developing of 4G in the following few to 10 years.

Conclusion:

Nowadays, wireless technology is getting popular and important in the network and the Internet field. In this paper, I briefly introduced the history background of 1G to 5G, compared the differences of 3G and 4G, and illustrated how 4G may work for more convenient and powerful in the future. 4G just right started from 2002 and there are many standards and technologies, which are still in developing process. Therefore, no one can really sure what the future 4G will look like and what services it will offer to people. However, we can get the general idea about 4G from academic research; 4G is the evolution based on 3G’s limitation and it will fulfill the idea of wwww. World Wide Wireless Web, offering more services and smooth global roaming with inexpensive cost.

References:

-           Internet

-           Mr. Mirza Ahmed Hussain,  Ex Dir. BTTB.