HSPA High-Speed Packet Access
HSDPA (High Speed Downlink Packet Access) can be achieved on the downlink rates up 14.4Mbit / s of. And the wireless interface control section by transferring the new adaptive modulation and coding from the radio network controller to a base station, a more efficient and faster scheduling of retransmission, HSDPA performance has been optimized and enhanced.
HSUPA (High Speed Uplink Packet Access) in the uplink is possible to achieve up 5.76Mbit / s speed. Base station uplink scheduling more efficient and faster retransmission control HSUPA achievement of superior performance.
Currently, although the mobile communications network technology is still diversified development trend, but due to concerns about the subsequent evolution of CDMA2000 and the obstacles encountered on the WiMAX business models and maturity of the technology, HSPA began to take hold . Recently, the world's leading operators have started to deploy HSPA network, fully proved this point. For operators and users, HSPA means higher rates, greater system capacity, lower latency, better business support. In 2007, the commercial speed HSPA technology continues to accelerate, there were already 162 HSDPA commercial networks, of which 96 networks can provide a data transfer rate of 3.6Mbit / s, some operators already offer 7.2Mbit / s rate of data services. South Korean operator KTF daily new 10000 HSPA subscribers, 40% of traffic is video traffic. Including mobile phone category, data cards and built-in notebook terminal and other terminals or access devices, global launch of HSPA terminal has reached 426 kinds. At the same time, higher upstream rates HSUPA technology has begun to apply. There are institutions and even predicted in 2011 50% of PC built-HSPA functionality.
are described as
HSDPA uses a shared downlink channel for data transmission, by introducing adaptive modulation and coding, hybrid automatic retransmission, fast scheduling, 16QAM technology to obtain higher data throughput, and can reduce the extent of data retransmission and transmission delay. Wherein the adaptive modulation and coding (AMC) is used to implement a radio link adaptation, and selects a different coding and modulation order of the channel under the circumstances. It refers to a hybrid automatic retransmission when an error occurs in the received data packet, within the allowed error range, the error correction performed prior to the introduction of forward error correction encoding, if beyond the error correction range, it sends a request message retransmission is required. Since hybrid automatic retransmission can automatically adapt to instantaneous channel conditions, and are less affected by measurement error and delay, and therefore when used in combination with adaptive modulation and coding, adaptive modulation and coding can provide coarse data rate selection, while mixing automatic retransmission may provide accurate rate adjustment based on channel conditions. In the HSDPA system, the radio base station increases rapidly medium access control entity is responsible for fast packet scheduling and real-time control of the HSDPA channel, the retransmission request is processed directly by the base station, which greatly accelerates the response speed of the system and shorten the processing delay system. According to radio channel quality indication, data traffic and traffic priority, etc., packet scheduling algorithm can quickly achieve the optimal allocation of shared resources. Process
and appears in the HSDPA technology matures in, HPUPA HSPA + and other emerging technologies. HPUPA introduced mainly to improve the data transmission rate of the mobile network the uplink direction. Its most significant feature is the addition of a new high-speed downlink shared channel and an uplink transport channel in HSDPA. While the radio base station adds the new cell, is responsible for scheduling and performs fast retransmission, etc., thereby reducing the transmission delay, retransmission speed increase.
HSPA + operators was low complexity, low-cost smooth evolution from HSPA way the LTE, it is reserved on the basis of the key technologies of HSPA, MIMO multi-antenna technology increases, improving the system capacity HSPA + high employed; and reliability; continuous packet connectivity using the program, reduces the potential discontinuous transmission, cost and time delay caused by frequent connection and reconnection suspension so as to increase the number of users, the capacity and efficiency of the system order modulation technique to improve the data transmission rate of the user. HSPA + is an all-IP, full-service network, it increases the capacity VoIP and other delay-sensitive services, reducing the delay in establishing a business, improve real-time business, and backward compatible with the existing WCDMA network, to better protect the user the original investment.
From a market perspective, HSDPA has a strong appeal in the development of high-speed wireless data services. Generally, the cost of data transmission is the sum of the operating costs and capital depreciation network. Network overhead is largely determined by the overall throughput of the partition of the base station. The cost of each base station is assumed constant, then the greater the amount of data transmitted by a base station, the lower the cost per megabyte of data transmitted. Compared with the EDGE and WCDMA, HSDPA improve spectral efficiency at reduced cost per bit of the transmission data. As a result, mobile operators can provide more services to a wider group of users at a lower price.
operators build a wireless network using HSDPA, may provide greater amount of data processing and user partition at a lower potential to network situation, improved data transmission capability allows operators to provide users with more It has a stronger attraction, richer new services and applications, and to meet consumer demand for video-on-demand, audio-on-demand, image-based text messaging and the growing wealth of location-based services and other content of the media business. Spectral efficiency advantages of HSDPA technology allows operators to lower the cost of providing such services, giving users superior to conventional technology experience.
Therefore, the main advantage of HSDPA technology that allows operators to cost-effectively expand capacity significantly in order to benefit from more cost-effective network, while access to high-margin business areas of the market share.
It is worth noting, HSDPA evolution also the direction of TD-SCDMA technology in my country. TD-HSDPA enhancement technique used mainly shared channel, high-order modulation, adaptive modulation and coding, hybrid automatic retransmission and fast cell selection. In addition, in order to achieve higher peak rates in order to improve the ability to support packet services, the TD-SCDMA system with the times, with a considerable competitive advantage with other systems, in addition to single-carrier HSDPA technology, China Communications Standards Association (CCSA ) also introduced a multi-carrier HSDPA technology for a TD-SCDMA system, the multi-carrier bundle to increase the TD-SCDMA system in the single-user peak rate, i.e. the channel resources on multiple carriers may be the same user service, the user may simultaneously receiving information transmitted according to a plurality of cell carriers. Thus, if the N carriers simultaneously transmit data to a user, the user may be obtained theoretically N times the original data rate. Since the introduction of multi-carrier technology, the network side adds data distribution processing function, the user terminal side adds data merge processing, both the structure changes, increased ability. There is no doubt, HSPA technology in my country's mobile communications market is bound to have broad space for development.