This tutorial covers TD-SCDMA basics, TD-SCDMA frame structure and comparison with WCDMA technology.
TD-SCDMA is the technology similar to WCDMA and is used in China. It stands for Time Division Synchronous Code Division Multiple Access. It is also referred as china's 3G standard similar to Europe's 3G (WCDMA). TD-SCDMA uses various frequency bands from 1785MHz to 2220 MHz range. It uses bandwidth of either 1.6MHz or 5 MHz based on Mcps requirement.
TD-SCDMA Frame structure
As shown in the figure 1, TD-SCDMA uses single unpaired spectrum for both downlink (DL) and uplink (UL) traffic. TDD is employed to provide access to both uplink and downlink traffic in different time slots on this shared spectrum. TD-SCDMA uses spectrum efficiently by allocating time slots as per data load requirement in downlink and uplink and hence it is ideal for asymmetric traffic.
Fig.2 TD-SCDMA frame structure
TD-SCDMA frame structure is shown in figure 2, which depicts frame hierarchy. In TD-SCDMA a super-frame of 720 ms duration is made of 72 radio frames of 10 ms duration each. Further each radio frame is divided into two sub frames each of 5ms. One sub frame is composed of 7 normal time slots used for downlink/uplink and 3 special time slots.
In 7 normal time slots, slot TS0 is used for downlink, slot TS1 for uplink and rest of time slots are allocated based on demand for traffic in downlink/uplink. 3 special time slots are used as DwPTS (downlink pilot timeslot), GP (guard period) and UpPTS (uplink pilot timeslot). DwPTS and UpPTS are used for downlink and uplink synchronization respectively.
For 1.28 Mcps TDD case, 1.6 MHz is allocated and for 3.84Mcps TDD case 5 MHZ is allocated. Information data bits are spread across using CDMA codes. 16 codes are allocated for each time slot.
TD-SCDMA Physical layer
Follow link below to read more on TD-SCDMA Physical layer modules used in transmitter part as per UTRA Physical Layer defined in 3GPP standard for TDD mode.
TD-SCDMA Physical layer.
Comparison between TD-SCDMA and WCDMA
For comparison between TD-SCDMA, WCDMA and CDMA2000, refer our page in terminology section which covers difference between these technologies,
TD-SCDMA chipset vendors, READ MORE
TD-SCDMA UE conformance testing
TD-SCDMA Forum, Website- www.tdscdma-forum.org/en/
What is Difference between
Frame structure of wireless standards, technologies
Frame structure of various wireless standards/technologies are mentioned below.
It include WiMAX, WLAN, Zigbee, GSM, GPRS, UMTS, LTE, TD-SCDMA, GPS, SDH, 11ac WLAN, AMPS, Ethernet, VLAN etc.
WiMAX physical layer Frame Structure as per 802.16d and 802.16e standards
WiMAX MAC layer Frame Structure as per OFDM 802.16d standard
Zigbee RF4CE Frame Structure
Zigbee physical layer Frame Structure
Zigbee MAC layer Frame Structure
GPRS Frame Structure
GPS Frame Structure
LTE Frame Structure
TD-SCDMA Frame Structure
UMTS Frame Structure
SONET Frame Structure
SDH Frame Structure
802.11ac PHY Frame Structure
802.11ac MAC layer Frame Structure
WLAN Frame Structure as per 802.11a,11b,11n,11ac standards
AMPS Frame Structure
Ethernet Frame Structure
VLAN Frame Structure
GSM Frame Structure