Wcdma

Chapter 6 WCDMA Chapter 6 6.1 INTRODUCTION This chapter presents the WCDMA air interface, referred also as UMTS terrestrial radio access (UTRA), substantial by the third-generation mappingnership project (3GPP). 3GPP has the goal to harmonize and regularise in stop the similar proposals from ETSI, ARIB, TTC, TTA, and T1. Table 6.1 lists the parameters of WCDMA. WCDMA has two modes characterized by the duplex dodging: FDD (frequency division duplex) and TDD (time division duplex), for operating with paired and unpaired bands, independently [1]. The TDD mode is described in Chapter 7. The scat rate of the system is 3.84 Mcps. The compose length is 10 ms and each frame is divided into 15 slots (2560 crisp/slot at the chip rate 3.84 Mcps). Spreading chemical elements range from 256 to 4 in the uplink and from 512 to 4 in the downlink. Thus, the respective modulation symbol rates part from 960 k symbols/s to 15 k symbols/s (7.5 k symbols/s) for FDD uplink . For separating bring from the same source, orthogonal variable spreading factor (OVSF) channelization codes are employ. In the downlink, grand codes with a 10-ms full stop (38400 chips at 3.84 Mcps) are used to elucidate different cells, with the veritable code itself length 218-1 chips.

In the uplink, Gold codes with a 10ms period, or alternatively short codes with a 256-chip period, are used to separate the different users. For the channel coding tercet options are support: convolutional coding, turbo coding, or no channel coding. highway coding endurance is indicated by upper layers. Bit interl eaving is used to randomize transmission e! rrors. The modulation scheme is QPSK. The common letter carrier wave lay has a raster of 200 kHz and can vary from 4.2 to 5.4 MHz. The different carrier spacings can be used to obtain suitable button up channel protections depending on the interference scenario. Figure 6.1 shows an example for the doer bandwidth of 15 MHz with three cell layers. Larger carrier spacing can be applied...If you want to get a full essay, mold it on our website: OrderCustomPaper.com

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