Lte Pdcch Design

Optimal Downlink Control Channel Resource

Allocation for LTE Systems

Balamurali

Motorola, India

Abstract—This paper presents optimal and efficient suboptimal resource allocation algorithms for the downlink control

channel of the Third Generation Partnership Project-Long Term

Evolution (3GPP-LTE) standard [1]. A novel formulation of this

resource allocation problem as a pure binary-integer program

called the set packing problem is performed. This problem has

been well-studied in operations research. In addition a greedy

heuristic sub-optimal algorithm that reduces the processing

complexity involved in finding the optimal solution and also

approaches the optimal performance is presented. Performance

comparisons of these proposed schemes based on Monte-Carlo

simulations in a 5 MHz bandwidth LTE system are provided.

The results prove that the proposed algorithms can significantly

improve the system’s cell-edge performance.

I. I NTRODUCTION

The number of mobile voice and/or data subscribers has

increased tremendously in recent years. The average data

consumption exceeds hundreds of Megabytes per subscriber

per month. The end users expect data performance similar

to the fixed lines. The operators request high data capacity

with low cost of data delivery. 3GPP-LTE is designed to

meet all these requirements. The goal is to achieve 2-4

times the spectral efficiency and user throughput and much

smaller latency compared to 3GPP High Speed Packet Access

(HSPA). To reach these goals, an efficient downlink control

channel design to reduce the overhead required to support

data transmission is specified in the LTE standard [2]. This

downlink control signalling includes information regarding

the scheduled resource blocks (RBs), modulation and coding

scheme (MCS), transmission mode and related hybrid ARQ

(HARQ) information to both the downlink and uplink user

equipments (UE). The downlink control channel in LTE is

either intended for a single user or...