Yannick Le Pezennec

Mobile broadband field network performance with HSPA

3GPP Release 7 introduced several new powerful features to the existing HSDPA (High Speed Downlink Packet Access) functionality including higher order modulation (SIMO 64 QAM - Single Input Multiple Output, 64 Quadrature Amplitude Modulation) and MIMO 16QAM (Multiple Input Multiple Output). These additional features - commonly referred to as “HSPA+” - aim at improving user experience by increasing further the spectrum efficiency of HSPA+ and is progressively being deployed by many 3G operators [1] around the globe at present as 64QAM and MIMO capable devices become more widely available. The objective of this paper is to provide an insight into the potential of HSPA+ technology as a means to enhance user experience against prior HSPA mobile broadband capabilities such as “HSDPA 7.2 and HSDPA 10.8 (SIMO 16QAM). The performance benchmark is the outcome of recent field tests pioneered by Vodafone, in its Vodafone Spain network, and carried out over commercial product platforms. As expected from theoretical assessments MIMO is proving to be the most promising feature from the HSPA+ set of features with field performance in excess of expectations - in particular at cell edge.

HSPA+ (2100 MHz) vs LTE (2600 MHz) spectral efficiency and latency comparison

High Speed Packet Access+ (HSPA+) has become widely deployed whilst the more recently specified Long Term Evolution (LTE) deployments are in their infancy. The objective of this paper is to provide a side by side field performance comparison between HSPA+ and LTE deployed in the 2100 MHz and 2600 MHz bands respectively reusing the same sites and antennas and using the most advanced mobile broadband feature readily available in the same radio environment. Separately, both of these technologies have been investigated however a comparison of both as part of the same field trial has received less attention. The performance comparison was carried out with comparable spectrum bandwidth (5 and 10 MHz) in a real network - Vodafone Spain - dedicated to the trial without any bias in terms of traffic or interference from other users. The exercise revealed that the latency performance difference is not as high as expected with less than 10 ms difference however the connection time is significantly improved. Most distinguishing factor in LTE downlink is the more efficient and robust usage of Multiple Input Multiple Output (MIMO) and 64 Quadrature Amplitude Modulation (QAM) altogether which outperforms HSPA+ even when using a less advantageous frequency band. In uplink LTE only outperforms HSPA+ in good radio conditions due to the possibility to use 16QAM modulation.