LTE UE Category and Class Definitions

In the same way that a variety of other systems adopted different categories for the handsets or user equipments, so too there are 3G LTE UE categories. These LTE categories define the standards to which a particular handset, dongle or other equipment will operate.

LTE UE category rationale

The LTE UE categories or UE classes are needed to ensure that the base station, or eNodeB, eNB can communicate correctly with the user equipment. By relaying the LTE UE category information to the base station, it is able to determine the performance of the UE and communicate with it accordingly.

As the LTE category defines the overall performance and the capabilities of the UE, it is possible for the eNB to communicate using capabilities that it knows the UE possesses. Accordingly the eNB will not communicate beyond the performance of the UE.

LTE UE category definitions

there are five different LTE UE categories that are defined. As can be seen in the table below, the different LTE UE categories have a wide range in the supported parameters and performance. LTE category 1, for example does not support MIMO, but LTE UE category five supports 4x4 MIMO.

It is also worth noting that UE class 1 does not offer the performance offered by that of the highest performance HSPA category. Additionally all LTE UE categories are capable of receiving transmissions from up to four antenna ports.

A summary of the different LTE UE category parameters provided by the 3GPP Rel 8 standard is given in the tables below.

Category	1	2	3	4	5
Downlink	10	50	100	150	300
Uplink	5	25	50	50	75

LTE UE category data rates

Category	1	2	3	4	5
Downlink	QPSK, 16QAM, 64QAM
Uplink	QPSK, 16QAM				QPSK, 16QAM, 64QAM

LTE UE category modulation formats supported

Category	1	2	3	4	5
2 Rx diversity	Assumed in performance requirements across all LTE UE categories
2 x 2 MIMO	Not supported	Mandatory
4 x 4 MIMO	Not supported				Mandatory

LTE UE category MIMO antenna configurations

Note: Bandwidth for all categories is 20 MHz.

LTE UE category summary

In the same way that category information is used for virtually all cellular systems from GPRS onwards, so the LTE UE category information is of great importance. While users may not be particularly aware of the category of their UE, it will match the performance an allow the eNB to communicate effectively with all the UEs that are connected to it.