We had the same speed problems with Verizon 3G after a couple years of not too bad speed. So we got Verizon 4G and in some areas it was better but not so much in other areas - even in 4G areas. Our download is almost always faster than our upload no matter what we use. It can vary dramatically depending on location and time of day. Telcel has several levels or types of internet. Below is some info I do not pretend to completely understand. If you look at your banda ancha window you will see letters in the lower left. This tells you the type of signal you are picking up. It can change by the minute depending on the tower etc. I probably have some of this wrong but maybe someone else can clarify.
EDGE
"Enhanced Data Rates for Global Evolution". Transmits data from three to four times the speed currently available which substantially improves the browsing experience on mobile data network benefits such as large file downloads and access to video and multimedia services faster.
GSM (Global System for Mobile Communications) 2G -- 9.6Kbps
GPRS (General packet radio services) 2.5G -- 35Kbps to 171kbps
EDGE (Enhanced Data rates for GSM Evolution) 2.75G -- 120Kbps to 384Kbps
UMTS (Universal Mobile Telecommunications System) 3G -- 384Kbps to 2Mbps
HSPA (software upgrade to UMTS) 3.5G -- 600Kbps to 10Mbps, averages 1-3Mbps
WiMAX/LTE "4G" -- 3Mbps to 6Mbps average, 10Mbps+ peak download speeds.
3G
Data service third generation type broadband with speeds up to 384 Kbps when sending and up to 1.5 Mbps in download information.
HSDPA: Up to 3.6 Mbps
HSDPA: Up to 7.2 Mbps
HSUPA: up to 5.76 Mbps
High-Speed Downlink Packet Access (HSDPA) is an enhanced 3G (third-generation) mobile-telephony communications protocol in the High-Speed Packet Access (HSPA) family, also dubbed 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data-transfer speeds and capacity. As of 2013 HSDPA deployments can support down-link speeds of up to 42.2 Mbit/s. HSPA+ offers further speed increases, providing speeds of up to 337.5 Mbit/s with Release 11 of the 3GPP standards.
UMTS
(Universal Mobile Telecommunications Service) is a third-generation (3G) broadband, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to 2 megabits per second (Mbps). UMTS offers a consistent set of services to mobile computer and phone users, no matter where they are located in the world. UMTS is based on the Global System for Mobile (GSM) communication standard. It is also endorsed by major standards bodies and manufacturers as the planned standard for mobile users around the world. Once UMTS is fully available, computer and phone users can be constantly attached to the Internet wherever they travel and, as they roam, will have the same set of capabilities. Users will have access through a combination of terrestrial wireless and satellite transmissions. Until UMTS is fully implemented, users can use multi-mode devices that switch to the currently available technology (such as GSM 900 and 1800) where UMTS is not yet available.