LTE has been designed as a completely packet-oriented multi service system, without the reliance on circuit-switched connection-oriented protocols prevalent in its predecessors. In LTE, this philosophy is applied across all the layers of the protocol stack. The route towards fast packet scheduling over the radio interface was already opened by HSDPA, which allowed the transmission … Read more
Different modulation methods corresponding to different transmitting abilities in air interface. R99/R4: QPSK HSDPA: QPSK or 16QAM The UTRAN air interface uses QPSK modulation in the downlink, although HSDPA may also employ 16 Quadrature Amplitude Modulation (16QAM). 16QAM requires good radio conditions to work well. As seen, with 16QAM also the amplitude of the signal … Read more
Peak data rate 100Mbps (DL) and 50Mbps (UL) to 20MHz Throughput increased by 3-4 times and 2-3 times for the downlink to uplink from HSDPA Rel6 (DL=14.4Mbps, to use transmitter sites that have been used in UTRA/GERAN Throughput increased by 3-4 times and 2-3 time UL=5.7Mbps) Spectrum efficiency by continuing as for the downlink to … Read more
A parallel 3GPP R8 project to LTE and SAE is the Evolved High Speed Packet Access, eHSPA, project (also referred to as HSPA+). The proposed eHSPA features represent a logical evolution from today’s HSDPA and HSUPA systems. Roughly speaking, the eHSPA project focuses on three areas: • Optimising HSPA for real-time packet data services, like … Read more