1×RTT (Single carrier radio transmission technology)

1×RTT, also known as Single Carrier Radio Transmission Technology, is a wireless communication standard used in CDMA (Code Division Multiple Access) networks. It is also sometimes referred to as 2.5G or 2.75G, as it is an intermediate technology between 2G and 3G networks. 1×RTT was introduced by Qualcomm in the late 1990s and became the first wireless standard to provide data speeds of up to 144 kbps.

In this article, we will explore the basics of 1×RTT technology, including how it works, its advantages and disadvantages, and its applications.

How 1×RTT Works 1×RTT is a wireless communication technology that uses CDMA to transmit data between mobile devices and cell towers. CDMA is a digital cellular technology that uses spread-spectrum techniques to allow multiple users to share the same frequency band simultaneously. This is achieved by encoding the data with unique codes, which are then used to separate the signals of different users.

The term "1×" in 1×RTT refers to the fact that it uses a single carrier frequency to transmit both voice and data. This is in contrast to 3G and 4G networks, which use multiple carrier frequencies to achieve higher data rates.

1×RTT uses a modulation scheme known as QPSK (Quadrature Phase Shift Keying) to modulate the data onto the carrier signal. QPSK is a form of digital modulation that uses four different phase angles to represent two bits of data at a time. This modulation scheme allows for higher data rates than the binary modulation used in 2G networks.

In 1×RTT, data is transmitted in packets known as frames. Each frame contains 20ms worth of data and is divided into 16 time slots, with each slot lasting 1.25ms. The data is transmitted in bursts during each time slot, with the bursts separated by guard intervals to prevent interference.

Advantages of 1×RTT One of the main advantages of 1×RTT is its compatibility with existing CDMA networks. 1×RTT was designed to be a software upgrade to existing CDMA networks, allowing carriers to offer higher data speeds without having to build a new network infrastructure. This made it an attractive option for carriers looking to upgrade their networks to support data services.

Another advantage of 1×RTT is its low latency. Latency is the amount of time it takes for data to travel from the sender to the receiver. In 1×RTT, the latency is typically around 100-200ms, which is significantly lower than the latency of 2G networks.

1×RTT also offers a relatively low cost per bit of data transmitted. This made it an attractive option for carriers looking to offer data services without having to invest in expensive new network infrastructure.

Disadvantages of 1×RTT One of the main disadvantages of 1×RTT is its relatively low data speeds. With a maximum data rate of 144 kbps, it is significantly slower than 3G and 4G networks. This limited the types of data services that could be offered over 1×RTT networks.

Another disadvantage of 1×RTT is its limited capacity. Because it uses a single carrier frequency, it is more susceptible to interference than 3G and 4G networks, which use multiple carrier frequencies. This limited the number of users that could be supported on a single 1×RTT cell.

Applications of 1×RTT 1×RTT was primarily used for mobile data services, such as web browsing and email, as well as for simple multimedia services such as picture messaging. It was also used for voice services, as it was compatible with existing CDMA voice networks. However, its low data speeds and limited capacity made it less suitable for more data-intensive applications, such as video streaming and online gaming.

Despite its limitations, 1×RTT played an important role in the evolution of wireless networks. It paved the way for the development of higher-speed wireless technologies, such as EV-DO (Evolution-Data Optimized) and HSPA (High-Speed Packet Access), which offered data speeds of up to 3.1 Mbps and 14.4 Mbps, respectively.

Conclusion 1×RTT was an important wireless technology that played a key role in the development of mobile data services. Its compatibility with existing CDMA networks and low latency made it an attractive option for carriers looking to offer data services without having to invest in expensive new network infrastructure.

However, its limited data speeds and capacity made it less suitable for more data-intensive applications, and it was eventually superseded by higher-speed wireless technologies such as EV-DO and HSPA.

Despite its limitations, 1×RTT was an important step in the evolution of wireless networks and paved the way for the development of the high-speed wireless technologies we use today.