Td-scdma Hsdpa Terminals Achieve-td-scdma, Hsdpa-communications Industry - China Dual Sim Tv Cell

Speaking, TD-SCDMA system HSDPA (High Speed Downlink Packet Access) terminal development

is lagging behind, to accelerate its development is an important factor to increase competitiveness. This paper analyzes the high-speed data business to achieve TD-SCDMA system, the importance and function of the HSDPA implementation mechanism in the terminals and solutions.

1, TD-SCDMA the importance of high-speed data services

Present, Japan and South Korea's 3G operators have 3G high-speed data services experience great success. Japan's DoCoMo in 2001 launched WCDMA-FOMA services, as of May 2004 had 400 million users, the revenue generated by its total income has accounted for more than 20%. Korea Telecom (SKT) in Q3 2003, the deployment of 1xEV-DO network, the company data service revenues account for average revenue per user (ARPU), the proportion rose to 34%. In the next few years, data services will still achieve substantial growth and become the third-generation (3G) mobile Communicate The main applications and the main source of income.

Multimedia applications in order to meet the growing needs of high-speed data transmission, the third generation mobile communication Cooperation Project Team (3GPP) announced a new high-speed data transmission technology?? HSDPA (High Speed Downlink Packet Access). The technology in WCDMA systems has been widely used. According to statistical data on telecommunications-related sector, the current global total of 123 HSDPA networks in 56 countries / regions plan to deploy, including 70 WCDMA-HSDPA networks in 39 countries / regions business, 14 WCDMA-HSDPA network has reached 3.6Mb / s rate. Terminal, the currently listed 66 models HSDPA terminals, of which 22 handset, PC card and paragraph 44 Router A total of 19 providers; There are also 13 built-in HSDPA function of PC, a total of eight providers.

The above figures we can see, high-speed data services is an important third-generation mobile communications service operator is the main source of income. TD-SCDMA If you want users to experience their excellent services in 2G, is bound to provide high-speed data services. China-made 3G standard TD-SCDMA and other 3G standards to a place of competition, high-speed data services also has important significance.

2, TD-SCDMA mobile terminals with high-speed downlink data, mechanisms and principles

2.1TD-SCDMA high speed downlink Main

TD-SCDMA standard in the 3GPPRelease5 version introduces HSDPA technology. The technology can not change the structure of the existing network to improve TD-SCDMA system downlink data rates, single-carrier theoretical value of 2.8Mb / s. HSDPA mainly introduced HARQ (hybrid automatic repeat) technology, AMC (Adaptive Modulation and Coding) technology, fast scheduling and higher order modulation technology.

HARQ (hybrid automatic repeat request) technology is the FEC (forward error correction) combined with ARQ error correction method using FEC error correction ability of technology to improve the system transmission efficiency, and technologies to improve the system through the ARQ transmission reliability. Originator sends the code not only error detection, but also have some error correction capability. Income received codeword decoder side, the first check for error conditions, if it can be self-correcting; If the error number of the decoding fails, then save the received data, and request the sender must retransmit the data. To some extent in this way avoid the FEC methods require complex equipment and ARQ decoding methods have poor continuity of information.

AMC (Adaptive Modulation and Coding) technology, the basic principle is the network side according to the channel to the actual situation of the current channel capacity, according to the capacity to determine the appropriate modulation coding, in order to send information as possible to achieve a higher rate of transmission of several . Moreover, for each user channel quality changes, AMC can provide the appropriate modulation coding scheme changes to get higher transmission data rates and spectrum efficiency. The combination of AMC and HARO can get good results: AMC to provide raw data rate selection, while HARQ data channel according to conditions on the data rate for a more fine-tuning.

Fast scheduling technology mainly refers to the original in the RNC (RadioNetworkController) packet scheduling functions implemented to achieve the transfer to the NodeB, thus greatly reducing data processing delay.

2.2TD-SCDMAHSDPA Terminal Implementation Mechanism TD-SCDMA system in order to implement HSDPA functionality, the introduction of a new transmission channel HS-DSCH (HighSpeed-DownlinkSharedChannel) and three new physical channels HS-PDSCH (HighSpeedPhysicalDownlinkSharedChannel), HS-SCCH (SharedControlChannelforHS-DSCH ), HS-SICH (SharedInformationChannelforHS-DSCH). With the introduction of MAC?-Hs entity to deal with MAC (MediumAccessControl) layer of HS-DSCH related functions, including the HARQ protocol processing, rearrangement, split scheduling.

(1) terminal side of the MAC-hs entity structure shown in Figure 1:

Among these is the rearrangement of HARQ entities and entities. MAC-hs detailed configuration information is controlled through MAC access node from the RRC (RadioResourceControl) level obtained.

HARQ entity responsible for HARQ protocol. In each TTI (TD-SCDMAHSDPA system TTI = 5ms), the terminal has a HARQ process is running, responsible for the implementation of all HARQ related tasks, such as dealing with ACK / NACK, etc.. HSDPA the HARQ adopted the most simple SAW (StopAndWait) mechanism. Although the SAW mechanism is very simple to achieve, but because the next block of data transfer a data block to wait until the confirmation message and its efficiency is relatively low. In order to improve resource utilization, you can configure the network side, a number of HARQ process at the same time. Thus, when a HARQ process in the confirmation message wait state, the additional HARQ process data can be transmitted.

Rearrangement entities according to the received TSN (transmit sequence number) to sort the data block, and order data blocks in turn transmitted to the split entity. When the received data blocks will not start a timer when a row (T1), the received data block buffer discrete entity in the rearrangement. When the timer T1 to when all the right pieces of data received are transmitted to the split entity.

Split the main entity is the MAC-hsPDU removed after the first resolution and the possible end of the fill bit removal, the resultant MAC-dPDU, and then sent to MAC-d entity for processing.

(2) HS-DSCH, HS-PDSCH, HS-SC

by: gaga

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